diff --git a/src/ui/public/agg_response/geo_json/_tooltip_formatter.js b/src/ui/public/agg_response/geo_json/_tooltip_formatter.js
index bb32a5e81821..f444d5b27d0d 100644
--- a/src/ui/public/agg_response/geo_json/_tooltip_formatter.js
+++ b/src/ui/public/agg_response/geo_json/_tooltip_formatter.js
@@ -3,20 +3,20 @@ import _ from 'lodash';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 export default function TileMapTooltipFormatter($compile, $rootScope, Private) {
 
-  var fieldFormats = Private(RegistryFieldFormatsProvider);
-  var $tooltipScope = $rootScope.$new();
-  var $el = $('<div>').html(require('ui/agg_response/geo_json/_tooltip.html'));
+  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  let $tooltipScope = $rootScope.$new();
+  let $el = $('<div>').html(require('ui/agg_response/geo_json/_tooltip.html'));
   $compile($el)($tooltipScope);
 
   return function tooltipFormatter(feature) {
     if (!feature) return '';
 
-    var value = feature.properties.value;
-    var acr = feature.properties.aggConfigResult;
-    var vis = acr.aggConfig.vis;
+    let value = feature.properties.value;
+    let acr = feature.properties.aggConfigResult;
+    let vis = acr.aggConfig.vis;
 
-    var metricAgg = acr.aggConfig;
-    var geoFormat = _.get(vis.aggs, 'byTypeName.geohash_grid[0].format');
+    let metricAgg = acr.aggConfig;
+    let geoFormat = _.get(vis.aggs, 'byTypeName.geohash_grid[0].format');
     if (!geoFormat) geoFormat = fieldFormats.getDefaultInstance('geo_point');
 
     $tooltipScope.details = [
diff --git a/src/ui/public/agg_response/geo_json/geo_json.js b/src/ui/public/agg_response/geo_json/geo_json.js
index c0e0b9b52e4b..6c01ac567792 100644
--- a/src/ui/public/agg_response/geo_json/geo_json.js
+++ b/src/ui/public/agg_response/geo_json/geo_json.js
@@ -3,7 +3,7 @@ import rowsToFeatures from 'ui/agg_response/geo_json/rows_to_features';
 import AggResponseGeoJsonTooltipFormatterProvider from 'ui/agg_response/geo_json/_tooltip_formatter';
 export default function TileMapConverterFn(Private, timefilter, $compile, $rootScope) {
 
-  var tooltipFormatter = Private(AggResponseGeoJsonTooltipFormatterProvider);
+  let tooltipFormatter = Private(AggResponseGeoJsonTooltipFormatterProvider);
 
   return function (vis, table) {
 
@@ -13,13 +13,13 @@ export default function TileMapConverterFn(Private, timefilter, $compile, $rootS
       });
     }
 
-    var geoI = columnIndex('segment');
-    var metricI = columnIndex('metric');
-    var geoAgg = _.get(table.columns, [geoI, 'aggConfig']);
-    var metricAgg = _.get(table.columns, [metricI, 'aggConfig']);
+    let geoI = columnIndex('segment');
+    let metricI = columnIndex('metric');
+    let geoAgg = _.get(table.columns, [geoI, 'aggConfig']);
+    let metricAgg = _.get(table.columns, [metricI, 'aggConfig']);
 
-    var features = rowsToFeatures(table, geoI, metricI);
-    var values = features.map(function (feature) {
+    let features = rowsToFeatures(table, geoI, metricI);
+    let values = features.map(function (feature) {
       return feature.properties.value;
     });
 
diff --git a/src/ui/public/agg_response/geo_json/rows_to_features.js b/src/ui/public/agg_response/geo_json/rows_to_features.js
index 6c65e09ab35b..634bfd26b533 100644
--- a/src/ui/public/agg_response/geo_json/rows_to_features.js
+++ b/src/ui/public/agg_response/geo_json/rows_to_features.js
@@ -12,19 +12,19 @@ function unwrap(val) {
 
 function convertRowsToFeatures(table, geoI, metricI) {
   return _.transform(table.rows, function (features, row) {
-    var geohash = unwrap(row[geoI]);
+    let geohash = unwrap(row[geoI]);
     if (!geohash) return;
 
     // fetch latLn of northwest and southeast corners, and center point
-    var location = decodeGeoHash(geohash);
+    let location = decodeGeoHash(geohash);
 
-    var centerLatLng = [
+    let centerLatLng = [
       location.latitude[2],
       location.longitude[2]
     ];
 
     // order is nw, ne, se, sw
-    var rectangle = [
+    let rectangle = [
       [location.latitude[0], location.longitude[0]],
       [location.latitude[0], location.longitude[1]],
       [location.latitude[1], location.longitude[1]],
diff --git a/src/ui/public/agg_response/hierarchical/_build_split.js b/src/ui/public/agg_response/hierarchical/_build_split.js
index 8435b3c521bd..f4eb0fdf764a 100644
--- a/src/ui/public/agg_response/hierarchical/_build_split.js
+++ b/src/ui/public/agg_response/hierarchical/_build_split.js
@@ -1,10 +1,10 @@
 import collectKeys from 'ui/agg_response/hierarchical/_collect_keys';
 import AggResponseHierarchicalTransformAggregationProvider from 'ui/agg_response/hierarchical/_transform_aggregation';
 export default function biuldSplitProvider(Private) {
-  var transformer = Private(AggResponseHierarchicalTransformAggregationProvider);
+  let transformer = Private(AggResponseHierarchicalTransformAggregationProvider);
   return function (agg, metric, aggData) {
     // Ceate the split structure
-    var split = { label: '', slices: { children: [] } };
+    let split = { label: '', slices: { children: [] } };
 
     // Transform the aggData into splits
     split.slices.children = transformer(agg, metric, aggData);
diff --git a/src/ui/public/agg_response/hierarchical/_collect_branch.js b/src/ui/public/agg_response/hierarchical/_collect_branch.js
index 97370399f0e4..5ad651838827 100644
--- a/src/ui/public/agg_response/hierarchical/_collect_branch.js
+++ b/src/ui/public/agg_response/hierarchical/_collect_branch.js
@@ -3,13 +3,13 @@ define(function () {
     // walk up the branch for each parent
     function walk(item, memo) {
       // record the the depth
-      var depth = item.depth - 1;
+      let depth = item.depth - 1;
 
       // Using the aggConfig determine what the field name is. If the aggConfig
       // doesn't exist (which means it's an _all agg) then use the level for
       // the field name
-      var col = item.aggConfig;
-      var field = (col && col.params && col.params.field && col.params.field.displayName)
+      let col = item.aggConfig;
+      let field = (col && col.params && col.params.field && col.params.field.displayName)
         || (col && col.label)
         || ('level ' + item.depth);
 
diff --git a/src/ui/public/agg_response/hierarchical/_collect_keys.js b/src/ui/public/agg_response/hierarchical/_collect_keys.js
index f19a3d8cf3b1..1b9a542462c7 100644
--- a/src/ui/public/agg_response/hierarchical/_collect_keys.js
+++ b/src/ui/public/agg_response/hierarchical/_collect_keys.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 export default function collectKeys(children) {
-  var nextChildren = _.pluck(children, 'children');
-  var keys = _.pluck(children, 'name');
+  let nextChildren = _.pluck(children, 'children');
+  let keys = _.pluck(children, 'name');
   return _(nextChildren)
   .map(collectKeys)
   .flattenDeep()
diff --git a/src/ui/public/agg_response/hierarchical/_create_raw_data.js b/src/ui/public/agg_response/hierarchical/_create_raw_data.js
index ae79c41665db..93b9c1b519bf 100644
--- a/src/ui/public/agg_response/hierarchical/_create_raw_data.js
+++ b/src/ui/public/agg_response/hierarchical/_create_raw_data.js
@@ -3,12 +3,12 @@ import extractBuckets from 'ui/agg_response/hierarchical/_extract_buckets';
 export default function (vis, resp) {
 
   // Create the initial results structure
-  var results = { rows: [] };
+  let results = { rows: [] };
 
   // Create a reference to the buckets and metrics
-  var metrics = vis.aggs.bySchemaGroup.metrics;
-  var buckets = vis.aggs.bySchemaGroup.buckets;
-  var aggs = [];
+  let metrics = vis.aggs.bySchemaGroup.metrics;
+  let buckets = vis.aggs.bySchemaGroup.buckets;
+  let aggs = [];
 
   if (buckets) {
     _.each(buckets, function (bucket) {
@@ -37,7 +37,7 @@ export default function (vis, resp) {
 
   // if there are no buckets then we need to just set the value and return
   if (!buckets) {
-    var value = resp.aggregations
+    let value = resp.aggregations
       && resp.aggregations[metrics[0].id]
       && resp.aggregations[metrics[0].id].value
       || resp.hits.total;
@@ -60,9 +60,9 @@ export default function (vis, resp) {
     // iterate through all the buckets
     _.each(extractBuckets(data[agg.id], agg), function (bucket) {
 
-      var _record = _.flattenDeep([record, bucket.key]);
+      let _record = _.flattenDeep([record, bucket.key]);
       _.each(metrics, function (metric) {
-        var value = bucket.doc_count;
+        let value = bucket.doc_count;
         if (bucket[metric.id] && !_.isUndefined(bucket[metric.id].value)) {
           value = bucket[metric.id].value;
         }
@@ -73,7 +73,7 @@ export default function (vis, resp) {
       // buckets. If it does then we need to keep on walking the tree.
       // This is where the recursion happens.
       if (agg._next) {
-        var nextBucket = bucket[agg._next.id];
+        let nextBucket = bucket[agg._next.id];
         if (nextBucket && nextBucket.buckets) {
           walkBuckets(agg._next, bucket, _record);
         }
diff --git a/src/ui/public/agg_response/hierarchical/_extract_buckets.js b/src/ui/public/agg_response/hierarchical/_extract_buckets.js
index f6228c62b579..e80f40866453 100644
--- a/src/ui/public/agg_response/hierarchical/_extract_buckets.js
+++ b/src/ui/public/agg_response/hierarchical/_extract_buckets.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 export default function (bucket, agg) {
   if (bucket && _.isPlainObject(bucket.buckets)) {
     return _.map(bucket.buckets, function (value, key) {
-      var item = _.cloneDeep(value);
+      let item = _.cloneDeep(value);
       item.key = agg ? agg.getKey(value, key) : key;
       return item;
     });
diff --git a/src/ui/public/agg_response/hierarchical/_hierarchical_tooltip_formatter.js b/src/ui/public/agg_response/hierarchical/_hierarchical_tooltip_formatter.js
index 0d4c88554ae3..f4acab3927a5 100644
--- a/src/ui/public/agg_response/hierarchical/_hierarchical_tooltip_formatter.js
+++ b/src/ui/public/agg_response/hierarchical/_hierarchical_tooltip_formatter.js
@@ -3,19 +3,19 @@ import $ from 'jquery';
 import collectBranch from 'ui/agg_response/hierarchical/_collect_branch';
 import numeral from 'numeral';
 export default function HierarchicalTooltipFormaterProvider($rootScope, $compile, $sce) {
-  var $tooltip = $(require('ui/agg_response/hierarchical/_tooltip.html'));
-  var $tooltipScope = $rootScope.$new();
+  let $tooltip = $(require('ui/agg_response/hierarchical/_tooltip.html'));
+  let $tooltipScope = $rootScope.$new();
 
   $compile($tooltip)($tooltipScope);
 
   return function (columns) {
     return function (event) {
-      var datum = event.datum;
+      let datum = event.datum;
 
       // Collect the current leaf and parents into an array of values
       $tooltipScope.rows = collectBranch(datum);
 
-      var metricCol = $tooltipScope.metricCol = _.find(columns, { categoryName: 'metric' });
+      let metricCol = $tooltipScope.metricCol = _.find(columns, { categoryName: 'metric' });
 
       // Map those values to what the tooltipSource.rows format.
       _.forEachRight($tooltipScope.rows, function (row, i, rows) {
diff --git a/src/ui/public/agg_response/hierarchical/_transform_aggregation.js b/src/ui/public/agg_response/hierarchical/_transform_aggregation.js
index 6078989cd13b..a176f2d3e015 100644
--- a/src/ui/public/agg_response/hierarchical/_transform_aggregation.js
+++ b/src/ui/public/agg_response/hierarchical/_transform_aggregation.js
@@ -4,14 +4,14 @@ import AggConfigResult from 'ui/vis/agg_config_result';
 export default function transformAggregationProvider(Private) {
   return function transformAggregation(agg, metric, aggData, parent) {
     return _.map(extractBuckets(aggData, agg), function (bucket) {
-      var aggConfigResult = new AggConfigResult(
+      let aggConfigResult = new AggConfigResult(
         agg,
         parent && parent.aggConfigResult,
         metric.getValue(bucket),
         agg.getKey(bucket)
       );
 
-      var branch = {
+      let branch = {
         name: agg.fieldFormatter()(bucket.key),
         size: aggConfigResult.value,
         aggConfig: agg,
@@ -27,7 +27,7 @@ export default function transformAggregationProvider(Private) {
       // If the next bucket exists and it has children the we need to
       // transform it as well. This is where the recursion happens.
       if (agg._next) {
-        var nextBucket = bucket[agg._next.id];
+        let nextBucket = bucket[agg._next.id];
         if (nextBucket && nextBucket.buckets) {
           branch.children = transformAggregation(agg._next, metric, nextBucket, branch);
         }
diff --git a/src/ui/public/agg_response/hierarchical/build_hierarchical_data.js b/src/ui/public/agg_response/hierarchical/build_hierarchical_data.js
index 7c64f4285c65..32c782bf6622 100644
--- a/src/ui/public/agg_response/hierarchical/build_hierarchical_data.js
+++ b/src/ui/public/agg_response/hierarchical/build_hierarchical_data.js
@@ -6,34 +6,34 @@ import AggConfigResult from 'ui/vis/agg_config_result';
 import AggResponseHierarchicalBuildSplitProvider from 'ui/agg_response/hierarchical/_build_split';
 import AggResponseHierarchicalHierarchicalTooltipFormatterProvider from 'ui/agg_response/hierarchical/_hierarchical_tooltip_formatter';
 export default function buildHierarchicalDataProvider(Private, Notifier) {
-  var buildSplit = Private(AggResponseHierarchicalBuildSplitProvider);
-  var tooltipFormatter = Private(AggResponseHierarchicalHierarchicalTooltipFormatterProvider);
+  let buildSplit = Private(AggResponseHierarchicalBuildSplitProvider);
+  let tooltipFormatter = Private(AggResponseHierarchicalHierarchicalTooltipFormatterProvider);
 
 
-  var notify = new Notifier({
+  let notify = new Notifier({
     location: 'Pie chart response converter'
   });
 
   return function (vis, resp) {
     // Create a refrenece to the buckets
-    var buckets = vis.aggs.bySchemaGroup.buckets;
+    let buckets = vis.aggs.bySchemaGroup.buckets;
 
 
     // Find the metric so it's easier to reference.
     // TODO: Change this to support multiple metrics.
-    var metric = vis.aggs.bySchemaGroup.metrics[0];
+    let metric = vis.aggs.bySchemaGroup.metrics[0];
 
     // Link each agg to the next agg. This will be
     // to identify the next bucket aggregation
     buckets = arrayToLinkedList(buckets);
 
     // Create the raw data to be used in the spy panel
-    var raw = createRawData(vis, resp);
+    let raw = createRawData(vis, resp);
 
     // If buckets is falsy then we should just return the aggs
     if (!buckets) {
-      var label = 'Count';
-      var value = resp.aggregations
+      let label = 'Count';
+      let value = resp.aggregations
         && resp.aggregations[metric.id]
         && resp.aggregations[metric.id].value
         || resp.hits.total;
@@ -50,8 +50,8 @@ export default function buildHierarchicalDataProvider(Private, Notifier) {
       };
     }
 
-    var firstAgg = buckets[0];
-    var aggData = resp.aggregations[firstAgg.id];
+    let firstAgg = buckets[0];
+    let aggData = resp.aggregations[firstAgg.id];
 
     if (!firstAgg._next && firstAgg.schema.name === 'split') {
       notify.error('Splitting charts without splitting slices is not supported. Pretending that we are just splitting slices.');
@@ -59,7 +59,7 @@ export default function buildHierarchicalDataProvider(Private, Notifier) {
 
     // start with splitting slices
     if (!firstAgg._next || firstAgg.schema.name === 'segment') {
-      var split = buildSplit(firstAgg, metric, aggData);
+      let split = buildSplit(firstAgg, metric, aggData);
       split.hits = resp.hits.total;
       split.raw = raw;
       split.tooltipFormatter = tooltipFormatter(raw.columns);
@@ -67,17 +67,17 @@ export default function buildHierarchicalDataProvider(Private, Notifier) {
     }
 
     // map the split aggregations into rows.
-    var rows = _.map(extractBuckets(aggData, firstAgg), function (bucket) {
-      var agg = firstAgg._next;
-      var split = buildSplit(agg, metric, bucket[agg.id]);
+    let rows = _.map(extractBuckets(aggData, firstAgg), function (bucket) {
+      let agg = firstAgg._next;
+      let split = buildSplit(agg, metric, bucket[agg.id]);
       // Since splits display labels we need to set it.
       split.label = firstAgg.fieldFormatter()(agg.getKey(bucket));
 
-      var displayName = firstAgg.fieldDisplayName();
+      let displayName = firstAgg.fieldDisplayName();
       if (!_.isEmpty(displayName)) split.label += ': ' + displayName;
 
       split.tooltipFormatter = tooltipFormatter(raw.columns);
-      var aggConfigResult = new AggConfigResult(firstAgg, null, null, firstAgg.getKey(bucket));
+      let aggConfigResult = new AggConfigResult(firstAgg, null, null, firstAgg.getKey(bucket));
       split.split = { aggConfig: firstAgg, aggConfigResult: aggConfigResult, key: bucket.key };
       _.each(split.slices.children, function (child) {
         child.aggConfigResult.$parent = aggConfigResult;
@@ -85,7 +85,7 @@ export default function buildHierarchicalDataProvider(Private, Notifier) {
       return split;
     });
 
-    var result = { hits: resp.hits.total, raw: raw };
+    let result = { hits: resp.hits.total, raw: raw };
     if (firstAgg.params.row) {
       result.rows = rows;
     } else {
diff --git a/src/ui/public/agg_response/point_series/_fake_x_aspect.js b/src/ui/public/agg_response/point_series/_fake_x_aspect.js
index a88978181b08..5f9516a421cc 100644
--- a/src/ui/public/agg_response/point_series/_fake_x_aspect.js
+++ b/src/ui/public/agg_response/point_series/_fake_x_aspect.js
@@ -2,10 +2,10 @@ import VisAggConfigProvider from 'ui/vis/agg_config';
 import AggTypesAggTypeProvider from 'ui/agg_types/agg_type';
 
 export default function PointSeriesFakeXAxis(Private) {
-  var AggConfig = Private(VisAggConfigProvider);
-  var AggType = Private(AggTypesAggTypeProvider);
+  let AggConfig = Private(VisAggConfigProvider);
+  let AggType = Private(AggTypesAggTypeProvider);
 
-  var allAgg = new AggType({
+  let allAgg = new AggType({
     name: 'all',
     title: 'All docs',
     ordered: false,
@@ -13,7 +13,7 @@ export default function PointSeriesFakeXAxis(Private) {
   });
 
   return function makeFakeXAxis(vis) {
-    var fake = new AggConfig(vis, {
+    let fake = new AggConfig(vis, {
       type: allAgg,
       schema: vis.type.schemas.all.byName.segment
     });
diff --git a/src/ui/public/agg_response/point_series/_get_aspects.js b/src/ui/public/agg_response/point_series/_get_aspects.js
index db8aaeff5cc8..f4978de29885 100644
--- a/src/ui/public/agg_response/point_series/_get_aspects.js
+++ b/src/ui/public/agg_response/point_series/_get_aspects.js
@@ -1,9 +1,9 @@
 import _ from 'lodash';
 import AggResponsePointSeriesFakeXAspectProvider from 'ui/agg_response/point_series/_fake_x_aspect';
 export default function PointSeriesGetAspects(Private) {
-  var fakeXAspect = Private(AggResponsePointSeriesFakeXAspectProvider);
+  let fakeXAspect = Private(AggResponsePointSeriesFakeXAspectProvider);
 
-  var map = {
+  let map = {
     segment: 'x',
     metric: 'y',
     radius: 'z',
@@ -12,12 +12,12 @@ export default function PointSeriesGetAspects(Private) {
   };
 
   function columnToAspect(aspects, col, i) {
-    var schema = col.aggConfig.schema.name;
+    let schema = col.aggConfig.schema.name;
 
-    var name = map[schema];
+    let name = map[schema];
     if (!name) throw new TypeError('unknown schema name "' + schema + '"');
 
-    var aspect = {
+    let aspect = {
       i: i,
       col: col,
       agg: col.aggConfig
@@ -36,7 +36,7 @@ export default function PointSeriesGetAspects(Private) {
    *                    may be undefined, a single aspect, or an array of aspects.
    */
   return function getAspects(vis, table) {
-    var aspects = _(table.columns)
+    let aspects = _(table.columns)
     // write each column into the aspects under it's group
     .transform(columnToAspect, {})
     // unwrap groups that only have one value, and validate groups that have more
diff --git a/src/ui/public/agg_response/point_series/_get_point.js b/src/ui/public/agg_response/point_series/_get_point.js
index 9d52d18bd536..266ba41ce5c8 100644
--- a/src/ui/public/agg_response/point_series/_get_point.js
+++ b/src/ui/public/agg_response/point_series/_get_point.js
@@ -5,10 +5,10 @@ export default function PointSeriesGetPoint() {
   }
 
   return function getPoint(x, series, yScale, row, y, z) {
-    var zRow = z && row[z.i];
-    var xRow = row[x.i];
+    let zRow = z && row[z.i];
+    let xRow = row[x.i];
 
-    var point = {
+    let point = {
       x: unwrap(xRow, '_all'),
       xi: xRow && xRow.$order,
       y: unwrap(row[y.i]),
diff --git a/src/ui/public/agg_response/point_series/_get_series.js b/src/ui/public/agg_response/point_series/_get_series.js
index 7c05f844a643..817ec2712d96 100644
--- a/src/ui/public/agg_response/point_series/_get_series.js
+++ b/src/ui/public/agg_response/point_series/_get_series.js
@@ -2,30 +2,30 @@ import _ from 'lodash';
 import AggResponsePointSeriesGetPointProvider from 'ui/agg_response/point_series/_get_point';
 import AggResponsePointSeriesAddToSiriProvider from 'ui/agg_response/point_series/_add_to_siri';
 export default function PointSeriesGetSeries(Private) {
-  var getPoint = Private(AggResponsePointSeriesGetPointProvider);
-  var addToSiri = Private(AggResponsePointSeriesAddToSiriProvider);
+  let getPoint = Private(AggResponsePointSeriesGetPointProvider);
+  let addToSiri = Private(AggResponsePointSeriesAddToSiriProvider);
 
   return function getSeries(rows, chart) {
-    var aspects = chart.aspects;
-    var multiY = _.isArray(aspects.y);
-    var yScale = chart.yScale;
-    var partGetPoint = _.partial(getPoint, aspects.x, aspects.series, yScale);
+    let aspects = chart.aspects;
+    let multiY = _.isArray(aspects.y);
+    let yScale = chart.yScale;
+    let partGetPoint = _.partial(getPoint, aspects.x, aspects.series, yScale);
 
-    var series = _(rows)
+    let series = _(rows)
     .transform(function (series, row) {
       if (!multiY) {
-        var point = partGetPoint(row, aspects.y, aspects.z);
+        let point = partGetPoint(row, aspects.y, aspects.z);
         if (point) addToSiri(series, point, point.series);
         return;
       }
 
       aspects.y.forEach(function (y) {
-        var point = partGetPoint(row, y, aspects.z);
+        let point = partGetPoint(row, y, aspects.z);
         if (!point) return;
 
-        var prefix = point.series ? point.series + ': ' : '';
-        var seriesId = prefix + y.agg.id;
-        var seriesLabel = prefix + y.col.title;
+        let prefix = point.series ? point.series + ': ' : '';
+        let seriesId = prefix + y.agg.id;
+        let seriesLabel = prefix + y.col.title;
 
         addToSiri(series, point, seriesId, seriesLabel);
       });
@@ -36,11 +36,11 @@ export default function PointSeriesGetSeries(Private) {
 
     if (multiY) {
       series = _.sortBy(series, function (siri) {
-        var firstVal = siri.values[0];
+        let firstVal = siri.values[0];
         let y;
 
         if (firstVal) {
-          var agg = firstVal.aggConfigResult.aggConfig;
+          let agg = firstVal.aggConfigResult.aggConfig;
           y = _.find(aspects.y, function (y) {
             return y.agg === agg;
           });
diff --git a/src/ui/public/agg_response/point_series/_init_x_axis.js b/src/ui/public/agg_response/point_series/_init_x_axis.js
index 3910621f701c..2a3584c3834f 100644
--- a/src/ui/public/agg_response/point_series/_init_x_axis.js
+++ b/src/ui/public/agg_response/point_series/_init_x_axis.js
@@ -1,14 +1,14 @@
 define(function () {
   return function PointSeriesInitX() {
     return function initXAxis(chart) {
-      var x = chart.aspects.x;
+      let x = chart.aspects.x;
       chart.xAxisFormatter = x.agg ? x.agg.fieldFormatter() : String;
       chart.xAxisLabel = x.col.title;
 
       if (!x.agg || !x.agg.type.ordered) return;
 
       chart.ordered = {};
-      var xAggOutput = x.agg.write();
+      let xAggOutput = x.agg.write();
       if (xAggOutput.params.interval) {
         chart.ordered.interval = xAggOutput.params.interval;
       }
diff --git a/src/ui/public/agg_response/point_series/_init_y_axis.js b/src/ui/public/agg_response/point_series/_init_y_axis.js
index 3c0e3313dd8b..edd3060fc85c 100644
--- a/src/ui/public/agg_response/point_series/_init_y_axis.js
+++ b/src/ui/public/agg_response/point_series/_init_y_axis.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 export default function PointSeriesInitYAxis() {
 
   return function initYAxis(chart) {
-    var y = chart.aspects.y;
-    var x = chart.aspects.x;
+    let y = chart.aspects.y;
+    let x = chart.aspects.x;
 
     if (_.isArray(y)) {
       // TODO: vis option should allow choosing this format
@@ -14,7 +14,7 @@ export default function PointSeriesInitYAxis() {
       chart.yAxisLabel = y.col.title;
     }
 
-    var xAggOutput = x.agg.write();
+    let xAggOutput = x.agg.write();
     chart.yScale = xAggOutput.metricScale || null;
   };
 };
diff --git a/src/ui/public/agg_response/point_series/_ordered_date_axis.js b/src/ui/public/agg_response/point_series/_ordered_date_axis.js
index ad4acd09b208..08b1d962252f 100644
--- a/src/ui/public/agg_response/point_series/_ordered_date_axis.js
+++ b/src/ui/public/agg_response/point_series/_ordered_date_axis.js
@@ -2,9 +2,9 @@ import moment from 'moment';
 export default function PointSeriesOrderedDateAxis(timefilter) {
 
   return function orderedDateAxis(vis, chart) {
-    var xAgg = chart.aspects.x.agg;
-    var buckets = xAgg.buckets;
-    var format = buckets.getScaledDateFormat();
+    let xAgg = chart.aspects.x.agg;
+    let buckets = xAgg.buckets;
+    let format = buckets.getScaledDateFormat();
 
     chart.xAxisFormatter = function (val) {
       return moment(val).format(format);
@@ -15,8 +15,8 @@ export default function PointSeriesOrderedDateAxis(timefilter) {
       interval: buckets.getInterval(),
     };
 
-    var axisOnTimeField = xAgg.fieldIsTimeField();
-    var bounds = buckets.getBounds();
+    let axisOnTimeField = xAgg.fieldIsTimeField();
+    let bounds = buckets.getBounds();
     if (bounds && axisOnTimeField) {
       chart.ordered.min = bounds.min;
       chart.ordered.max = bounds.max;
diff --git a/src/ui/public/agg_response/point_series/_tooltip_formatter.js b/src/ui/public/agg_response/point_series/_tooltip_formatter.js
index 60a9627ea55d..715d692127d1 100644
--- a/src/ui/public/agg_response/point_series/_tooltip_formatter.js
+++ b/src/ui/public/agg_response/point_series/_tooltip_formatter.js
@@ -1,22 +1,22 @@
 import $ from 'jquery';
 export default function PointSeriesTooltipFormatter($compile, $rootScope) {
 
-  var $tooltipScope = $rootScope.$new();
-  var $tooltip = $(require('ui/agg_response/point_series/_tooltip.html'));
+  let $tooltipScope = $rootScope.$new();
+  let $tooltip = $(require('ui/agg_response/point_series/_tooltip.html'));
   $compile($tooltip)($tooltipScope);
 
   return function tooltipFormatter(event) {
-    var datum = event.datum;
+    let datum = event.datum;
     if (!datum || !datum.aggConfigResult) return '';
 
-    var details = $tooltipScope.details = [];
-    var result = { $parent: datum.aggConfigResult };
+    let details = $tooltipScope.details = [];
+    let result = { $parent: datum.aggConfigResult };
 
     function addDetail(result) {
-      var agg = result.aggConfig;
-      var value = result.value;
+      let agg = result.aggConfig;
+      let value = result.value;
 
-      var detail = {
+      let detail = {
         value: agg.fieldFormatter()(value),
         label: agg.makeLabel()
       };
diff --git a/src/ui/public/agg_response/point_series/point_series.js b/src/ui/public/agg_response/point_series/point_series.js
index f44c7fdc466c..0a2ccd90729c 100644
--- a/src/ui/public/agg_response/point_series/point_series.js
+++ b/src/ui/public/agg_response/point_series/point_series.js
@@ -7,23 +7,23 @@ import AggResponsePointSeriesOrderedDateAxisProvider from 'ui/agg_response/point
 import AggResponsePointSeriesTooltipFormatterProvider from 'ui/agg_response/point_series/_tooltip_formatter';
 export default function PointSeriesProvider(Private) {
 
-  var getSeries = Private(AggResponsePointSeriesGetSeriesProvider);
-  var getAspects = Private(AggResponsePointSeriesGetAspectsProvider);
-  var initYAxis = Private(AggResponsePointSeriesInitYAxisProvider);
-  var initXAxis = Private(AggResponsePointSeriesInitXAxisProvider);
-  var setupOrderedDateXAxis = Private(AggResponsePointSeriesOrderedDateAxisProvider);
-  var tooltipFormatter = Private(AggResponsePointSeriesTooltipFormatterProvider);
+  let getSeries = Private(AggResponsePointSeriesGetSeriesProvider);
+  let getAspects = Private(AggResponsePointSeriesGetAspectsProvider);
+  let initYAxis = Private(AggResponsePointSeriesInitYAxisProvider);
+  let initXAxis = Private(AggResponsePointSeriesInitXAxisProvider);
+  let setupOrderedDateXAxis = Private(AggResponsePointSeriesOrderedDateAxisProvider);
+  let tooltipFormatter = Private(AggResponsePointSeriesTooltipFormatterProvider);
 
   return function pointSeriesChartDataFromTable(vis, table) {
-    var chart = {};
-    var aspects = chart.aspects = getAspects(vis, table);
+    let chart = {};
+    let aspects = chart.aspects = getAspects(vis, table);
 
     chart.tooltipFormatter = tooltipFormatter;
 
     initXAxis(chart);
     initYAxis(chart);
 
-    var datedX = aspects.x.agg.type.ordered && aspects.x.agg.type.ordered.date;
+    let datedX = aspects.x.agg.type.ordered && aspects.x.agg.type.ordered.date;
     if (datedX) {
       setupOrderedDateXAxis(vis, chart);
     }
diff --git a/src/ui/public/agg_response/tabify/_buckets.js b/src/ui/public/agg_response/tabify/_buckets.js
index 965597be9bd0..7d05c83a882b 100644
--- a/src/ui/public/agg_response/tabify/_buckets.js
+++ b/src/ui/public/agg_response/tabify/_buckets.js
@@ -15,7 +15,7 @@ export default function AggResponseBucketsProvider() {
   }
 
   Buckets.prototype.forEach = function (fn) {
-    var buckets = this.buckets;
+    let buckets = this.buckets;
 
     if (this.objectMode) {
       this._keys.forEach(function (key) {
diff --git a/src/ui/public/agg_response/tabify/_get_columns.js b/src/ui/public/agg_response/tabify/_get_columns.js
index 1ddda56b1417..b9268891cadc 100644
--- a/src/ui/public/agg_response/tabify/_get_columns.js
+++ b/src/ui/public/agg_response/tabify/_get_columns.js
@@ -1,10 +1,10 @@
 import _ from 'lodash';
 import VisAggConfigProvider from 'ui/vis/agg_config';
 export default function GetColumnsProvider(Private) {
-  var AggConfig = Private(VisAggConfigProvider);
+  let AggConfig = Private(VisAggConfigProvider);
 
   return function getColumns(vis, minimal) {
-    var aggs = vis.aggs.getResponseAggs();
+    let aggs = vis.aggs.getResponseAggs();
 
     if (minimal == null) minimal = !vis.isHierarchical();
 
@@ -23,10 +23,10 @@ export default function GetColumnsProvider(Private) {
     }
 
     // supposed to be bucket,...metrics,bucket,...metrics
-    var columns = [];
+    let columns = [];
 
     // seperate the metrics
-    var grouped = _.groupBy(aggs, function (agg) {
+    let grouped = _.groupBy(aggs, function (agg) {
       return agg.schema.group;
     });
 
diff --git a/src/ui/public/agg_response/tabify/_response_writer.js b/src/ui/public/agg_response/tabify/_response_writer.js
index be27f4518dc9..53f1ee01782a 100644
--- a/src/ui/public/agg_response/tabify/_response_writer.js
+++ b/src/ui/public/agg_response/tabify/_response_writer.js
@@ -4,9 +4,9 @@ import AggResponseTabifyTableProvider from 'ui/agg_response/tabify/_table';
 import AggResponseTabifyTableGroupProvider from 'ui/agg_response/tabify/_table_group';
 import AggResponseTabifyGetColumnsProvider from 'ui/agg_response/tabify/_get_columns';
 export default function TabbedAggResponseWriterProvider(Private) {
-  var Table = Private(AggResponseTabifyTableProvider);
-  var TableGroup = Private(AggResponseTabifyTableGroupProvider);
-  var getColumns = Private(AggResponseTabifyGetColumnsProvider);
+  let Table = Private(AggResponseTabifyTableProvider);
+  let TableGroup = Private(AggResponseTabifyTableGroupProvider);
+  let getColumns = Private(AggResponseTabifyGetColumnsProvider);
 
 
   _.class(SplitAcr).inherits(AggConfigResult);
@@ -25,7 +25,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
     this.opts = opts || {};
     this.rowBuffer = [];
 
-    var visIsHier = vis.isHierarchical();
+    let visIsHier = vis.isHierarchical();
 
     // do the options allow for splitting? we will only split if true and
     // tabify calls the split method.
@@ -67,9 +67,9 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @return {Table/TableGroup} table - the created table
    */
   TabbedAggResponseWriter.prototype._table = function (group, agg, key) {
-    var Class = (group) ? TableGroup : Table;
-    var table = new Class();
-    var parent = this.splitStack[0];
+    let Class = (group) ? TableGroup : Table;
+    let table = new Class();
+    let parent = this.splitStack[0];
 
     if (group) {
       table.aggConfig = agg;
@@ -95,7 +95,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @param  {function} block - a function to execute for each sub bucket
    */
   TabbedAggResponseWriter.prototype.split = function (agg, buckets, block) {
-    var self = this;
+    let self = this;
 
     if (!self.canSplit) {
       throw new Error('attempted to split when splitting is disabled');
@@ -105,11 +105,11 @@ export default function TabbedAggResponseWriterProvider(Private) {
 
     buckets.forEach(function (bucket, key) {
       // find the existing split that we should extend
-      var tableGroup = _.find(self.splitStack[0].tables, { aggConfig: agg, key: key });
+      let tableGroup = _.find(self.splitStack[0].tables, { aggConfig: agg, key: key });
       // create the split if it doesn't exist yet
       if (!tableGroup) tableGroup = self._table(true, agg, key);
 
-      var splitAcr = false;
+      let splitAcr = false;
       if (self.asAggConfigResults) {
         splitAcr = self._injectParentSplit(agg, key);
       }
@@ -127,7 +127,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
   };
 
   TabbedAggResponseWriter.prototype._removeAggFromColumns = function (agg) {
-    var i = _.findIndex(this.columns, function (col) {
+    let i = _.findIndex(this.columns, function (col) {
       return col.aggConfig === agg;
     });
 
@@ -140,8 +140,8 @@ export default function TabbedAggResponseWriterProvider(Private) {
 
     // hierarchical vis creats additional columns for each bucket
     // we will remove those too
-    var mCol = this.columns.splice(i, 1).pop();
-    var mI = _.findIndex(this.aggStack, function (agg) {
+    let mCol = this.columns.splice(i, 1).pop();
+    let mI = _.findIndex(this.aggStack, function (agg) {
       return agg === mCol.aggConfig;
     });
 
@@ -160,12 +160,12 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @return {SplitAcr} - the AggConfigResult created for the split bucket
    */
   TabbedAggResponseWriter.prototype._injectParentSplit = function (agg, key) {
-    var oldList = this.acrStack;
-    var newList = this.acrStack = [];
+    let oldList = this.acrStack;
+    let newList = this.acrStack = [];
 
     // walk from right to left through the old stack
     // and move things to the new stack
-    var injected = false;
+    let injected = false;
 
     if (!oldList.length) {
       injected = new SplitAcr(agg, null, key);
@@ -175,7 +175,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
 
     // walk from right to left, emptying the previous list
     while (oldList.length) {
-      var acr = oldList.pop();
+      let acr = oldList.pop();
 
       // ignore other splits
       if (acr instanceof SplitAcr) {
@@ -189,11 +189,11 @@ export default function TabbedAggResponseWriterProvider(Private) {
         newList.unshift(injected);
       }
 
-      var newAcr = new AggConfigResult(acr.aggConfig, newList[0], acr.value, acr.aggConfig.getKey(acr));
+      let newAcr = new AggConfigResult(acr.aggConfig, newList[0], acr.value, acr.aggConfig.getKey(acr));
       newList.unshift(newAcr);
 
       // and replace the acr in the row buffer if its there
-      var rowI = this.rowBuffer.indexOf(acr);
+      let rowI = this.rowBuffer.indexOf(acr);
       if (rowI > -1) {
         this.rowBuffer[rowI] = newAcr;
       }
@@ -215,7 +215,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
       value = new AggConfigResult(agg, this.acrStack[0], value, value);
     }
 
-    var staskResult = this.asAggConfigResults && value.type === 'bucket';
+    let staskResult = this.asAggConfigResults && value.type === 'bucket';
 
     this.rowBuffer.push(value);
     if (staskResult) this.acrStack.unshift(value);
@@ -237,14 +237,14 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @return {undefined}
    */
   TabbedAggResponseWriter.prototype.row = function (buffer) {
-    var cells = buffer || this.rowBuffer.slice(0);
+    let cells = buffer || this.rowBuffer.slice(0);
 
     if (!this.partialRows && cells.length < this.columns.length) {
       return;
     }
 
-    var split = this.splitStack[0];
-    var table = split.tables[0] || this._table(false);
+    let split = this.splitStack[0];
+    let table = split.tables[0] || this._table(false);
 
     while (cells.length < this.columns.length) cells.push('');
     table.rows.push(cells);
@@ -257,7 +257,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @return {object} - the final table-tree
    */
   TabbedAggResponseWriter.prototype.response = function () {
-    var columns = this.columns;
+    let columns = this.columns;
 
     // give the columns some metadata
     columns.map(function (col) {
@@ -272,7 +272,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
 
     if (this.canSplit) return this.root;
 
-    var table = this.root.tables[0];
+    let table = this.root.tables[0];
     if (!table) return;
 
     delete table.$parent;
diff --git a/src/ui/public/agg_response/tabify/tabify.js b/src/ui/public/agg_response/tabify/tabify.js
index a74a340dc52e..722a1a12b803 100644
--- a/src/ui/public/agg_response/tabify/tabify.js
+++ b/src/ui/public/agg_response/tabify/tabify.js
@@ -4,15 +4,15 @@ import AggResponseTabifyResponseWriterProvider from 'ui/agg_response/tabify/_res
 import AggResponseTabifyBucketsProvider from 'ui/agg_response/tabify/_buckets';
 export default function tabifyAggResponseProvider(Private, Notifier) {
 
-  var AggConfig = Private(VisAggConfigProvider);
-  var TabbedAggResponseWriter = Private(AggResponseTabifyResponseWriterProvider);
-  var Buckets = Private(AggResponseTabifyBucketsProvider);
-  var notify = new Notifier({ location: 'agg_response/tabify'});
+  let AggConfig = Private(VisAggConfigProvider);
+  let TabbedAggResponseWriter = Private(AggResponseTabifyResponseWriterProvider);
+  let Buckets = Private(AggResponseTabifyBucketsProvider);
+  let notify = new Notifier({ location: 'agg_response/tabify'});
 
   function tabifyAggResponse(vis, esResponse, respOpts) {
-    var write = new TabbedAggResponseWriter(vis, respOpts);
+    let write = new TabbedAggResponseWriter(vis, respOpts);
 
-    var topLevelBucket = _.assign({}, esResponse.aggregations, {
+    let topLevelBucket = _.assign({}, esResponse.aggregations, {
       doc_count: esResponse.hits.total
     });
 
@@ -31,13 +31,13 @@ export default function tabifyAggResponseProvider(Private, Notifier) {
    * @returns {undefined}
    */
   function collectBucket(write, bucket, key) {
-    var agg = write.aggStack.shift();
+    let agg = write.aggStack.shift();
 
     switch (agg.schema.group) {
       case 'buckets':
-        var buckets = new Buckets(bucket[agg.id]);
+        let buckets = new Buckets(bucket[agg.id]);
         if (buckets.length) {
-          var splitting = write.canSplit && agg.schema.name === 'split';
+          let splitting = write.canSplit && agg.schema.name === 'split';
           if (splitting) {
             write.split(agg, buckets, function forEachBucket(subBucket, key) {
               collectBucket(write, subBucket, agg.getKey(subBucket), key);
@@ -63,7 +63,7 @@ export default function tabifyAggResponseProvider(Private, Notifier) {
         }
         break;
       case 'metrics':
-        var value = agg.getValue(bucket);
+        let value = agg.getValue(bucket);
         write.cell(agg, value, function () {
           if (!write.aggStack.length) {
             // row complete
@@ -82,7 +82,7 @@ export default function tabifyAggResponseProvider(Private, Notifier) {
   // write empty values for each bucket agg, then write
   // the metrics from the initial bucket using collectBucket()
   function passEmptyBuckets(write, bucket, key) {
-    var agg = write.aggStack.shift();
+    let agg = write.aggStack.shift();
 
     switch (agg.schema.group) {
       case 'metrics':
diff --git a/src/ui/public/agg_table/agg_table.js b/src/ui/public/agg_table/agg_table.js
index 5c2017325b53..f44961b4e3a3 100644
--- a/src/ui/public/agg_table/agg_table.js
+++ b/src/ui/public/agg_table/agg_table.js
@@ -24,7 +24,7 @@ uiModules
       return compileRecursiveDirective.compile($el);
     },
     controller: function ($scope) {
-      var self = this;
+      let self = this;
 
       self.sort = null;
       self._saveAs = require('@spalger/filesaver').saveAs;
@@ -34,15 +34,15 @@ uiModules
       };
 
       self.exportAsCsv = function (formatted) {
-        var csv = new Blob([self.toCsv(formatted)], { type: 'text/plain' });
+        let csv = new Blob([self.toCsv(formatted)], { type: 'text/plain' });
         self._saveAs(csv, self.csv.filename);
       };
 
       self.toCsv = function (formatted) {
-        var rows = $scope.table.rows;
-        var columns = formatted ? $scope.formattedColumns : $scope.table.columns;
-        var nonAlphaNumRE = /[^a-zA-Z0-9]/;
-        var allDoubleQuoteRE = /"/g;
+        let rows = $scope.table.rows;
+        let columns = formatted ? $scope.formattedColumns : $scope.table.columns;
+        let nonAlphaNumRE = /[^a-zA-Z0-9]/;
+        let allDoubleQuoteRE = /"/g;
 
         function escape(val) {
           if (!formatted && _.isObject(val)) val = val.valueOf();
@@ -54,7 +54,7 @@ uiModules
         }
 
         // escape each cell in each row
-        var csvRows = rows.map(function (row) {
+        let csvRows = rows.map(function (row) {
           return row.map(escape);
         });
 
@@ -69,7 +69,7 @@ uiModules
       };
 
       $scope.$watch('table', function () {
-        var table = $scope.table;
+        let table = $scope.table;
 
         if (!table) {
           $scope.rows = null;
@@ -80,14 +80,14 @@ uiModules
         self.csv.filename = ($scope.exportTitle || table.title() || 'table') + '.csv';
         $scope.rows = table.rows;
         $scope.formattedColumns = table.columns.map(function (col, i) {
-          var agg = $scope.table.aggConfig(col);
-          var field = agg.field();
-          var formattedColumn = {
+          let agg = $scope.table.aggConfig(col);
+          let field = agg.field();
+          let formattedColumn = {
             title: col.title,
             filterable: field && field.filterable && agg.schema.group === 'buckets'
           };
 
-          var last = i === (table.columns.length - 1);
+          let last = i === (table.columns.length - 1);
 
           if (last || (agg.schema.group === 'metrics')) {
             formattedColumn.class = 'visualize-table-right';
diff --git a/src/ui/public/agg_table/agg_table_group.js b/src/ui/public/agg_table/agg_table_group.js
index 040f75841d42..1b133f57b36c 100644
--- a/src/ui/public/agg_table/agg_table_group.js
+++ b/src/ui/public/agg_table/agg_table_group.js
@@ -25,10 +25,10 @@ uiModules
 
             if (!group || !group.tables.length) return;
 
-            var firstTable = group.tables[0];
-            var params = firstTable.aggConfig && firstTable.aggConfig.params;
+            let firstTable = group.tables[0];
+            let params = firstTable.aggConfig && firstTable.aggConfig.params;
             // render groups that have Table children as if they were rows, because iteration is cleaner
-            var childLayout = (params && !params.row) ? 'columns' : 'rows';
+            let childLayout = (params && !params.row) ? 'columns' : 'rows';
 
             $scope[childLayout] = group.tables;
           });
diff --git a/src/ui/public/agg_types/agg_params.js b/src/ui/public/agg_types/agg_params.js
index 1c5aa3a52e32..d6c435c214b4 100644
--- a/src/ui/public/agg_types/agg_params.js
+++ b/src/ui/public/agg_types/agg_params.js
@@ -10,7 +10,7 @@ import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function AggParamsFactory(Private) {
 
 
-  var paramTypeMap = {
+  let paramTypeMap = {
     field: Private(AggTypesParamTypesFieldProvider),
     optioned: Private(AggTypesParamTypesOptionedProvider),
     regex: Private(AggTypesParamTypesRegexProvider),
@@ -37,8 +37,8 @@ export default function AggParamsFactory(Private) {
     AggParams.Super.call(this, {
       index: ['name'],
       initialSet: params.map(function (config) {
-        var type = config.name === 'field' ? config.name : config.type;
-        var Class = paramTypeMap[type] || paramTypeMap._default;
+        let type = config.name === 'field' ? config.name : config.type;
+        let Class = paramTypeMap[type] || paramTypeMap._default;
         return new Class(config);
       })
     });
@@ -59,7 +59,7 @@ export default function AggParamsFactory(Private) {
    *         are dependent on the AggParam#write methods which should be studied for each AggType.
    */
   AggParams.prototype.write = function (aggConfig, locals) {
-    var output = { params: {} };
+    let output = { params: {} };
     locals = locals || {};
 
     this.forEach(function (param) {
diff --git a/src/ui/public/agg_types/agg_type.js b/src/ui/public/agg_types/agg_type.js
index d262d5077664..64f9db58e33e 100644
--- a/src/ui/public/agg_types/agg_type.js
+++ b/src/ui/public/agg_types/agg_type.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 import AggTypesAggParamsProvider from 'ui/agg_types/agg_params';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 export default function AggTypeFactory(Private) {
-  var AggParams = Private(AggTypesAggParamsProvider);
-  var fieldFormats = Private(RegistryFieldFormatsProvider);
+  let AggParams = Private(AggTypesAggParamsProvider);
+  let fieldFormats = Private(RegistryFieldFormatsProvider);
 
   /**
    * Generic AggType Constructor
@@ -142,7 +142,7 @@ export default function AggTypeFactory(Private) {
    * @return {FieldFromat}
    */
   AggType.prototype.getFormat = function (agg) {
-    var field = agg.field();
+    let field = agg.field();
     return field ? field.format : fieldFormats.getDefaultInstance('string');
   };
 
diff --git a/src/ui/public/agg_types/buckets/_bucket_agg_type.js b/src/ui/public/agg_types/buckets/_bucket_agg_type.js
index d47006baa55e..4249ec29be71 100644
--- a/src/ui/public/agg_types/buckets/_bucket_agg_type.js
+++ b/src/ui/public/agg_types/buckets/_bucket_agg_type.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import AggTypesAggTypeProvider from 'ui/agg_types/agg_type';
 export default function BucketAggTypeProvider(Private) {
-  var AggType = Private(AggTypesAggTypeProvider);
+  let AggType = Private(AggTypesAggTypeProvider);
 
   _.class(BucketAggType).inherits(AggType);
   function BucketAggType(config) {
diff --git a/src/ui/public/agg_types/buckets/_bucket_count_between.js b/src/ui/public/agg_types/buckets/_bucket_count_between.js
index 9acc16c66e04..3fbcd3e72334 100644
--- a/src/ui/public/agg_types/buckets/_bucket_count_between.js
+++ b/src/ui/public/agg_types/buckets/_bucket_count_between.js
@@ -13,19 +13,19 @@ export default function BucketCountBetweenProvider() {
    * @return {null|number}
    */
   function bucketCountBetween(aggConfigA, aggConfigB) {
-    var aggs = aggConfigA.vis.aggs.getRequestAggs();
+    let aggs = aggConfigA.vis.aggs.getRequestAggs();
 
-    var aIndex = aggs.indexOf(aggConfigA);
-    var bIndex = aggs.indexOf(aggConfigB);
+    let aIndex = aggs.indexOf(aggConfigA);
+    let bIndex = aggs.indexOf(aggConfigB);
 
     if (aIndex === -1 || bIndex === -1) {
       return null;
     }
 
     // return a negative distance, if b is before a
-    var negative = (aIndex > bIndex);
+    let negative = (aIndex > bIndex);
 
-    var count = aggs
+    let count = aggs
       .slice(Math.min(aIndex, bIndex), Math.max(aIndex, bIndex))
       .reduce(function (count, cfg) {
         if (cfg === aggConfigA || cfg === aggConfigB || cfg.schema.group !== 'buckets') {
diff --git a/src/ui/public/agg_types/buckets/_interval_options.js b/src/ui/public/agg_types/buckets/_interval_options.js
index 0dcdf7989c20..f1a8f151898d 100644
--- a/src/ui/public/agg_types/buckets/_interval_options.js
+++ b/src/ui/public/agg_types/buckets/_interval_options.js
@@ -3,7 +3,7 @@ import 'ui/directives/input_whole_number';
 export default function IntervalOptionsService(Private) {
 
   // shorthand
-  var ms = function (type) { return moment.duration(1, type).asMilliseconds(); };
+  let ms = function (type) { return moment.duration(1, type).asMilliseconds(); };
 
   return [
     {
diff --git a/src/ui/public/agg_types/buckets/create_filter/date_histogram.js b/src/ui/public/agg_types/buckets/create_filter/date_histogram.js
index da88378324b7..ce3a85c8b909 100644
--- a/src/ui/public/agg_types/buckets/create_filter/date_histogram.js
+++ b/src/ui/public/agg_types/buckets/create_filter/date_histogram.js
@@ -3,8 +3,8 @@ import buildRangeFilter from 'ui/filter_manager/lib/range';
 export default function createDateHistogramFilterProvider(Private) {
 
   return function (agg, key) {
-    var start = moment(key);
-    var interval = agg.buckets.getInterval();
+    let start = moment(key);
+    let interval = agg.buckets.getInterval();
 
     return buildRangeFilter(agg.params.field, {
       gte: start.valueOf(),
diff --git a/src/ui/public/agg_types/buckets/create_filter/date_range.js b/src/ui/public/agg_types/buckets/create_filter/date_range.js
index fba9d3c64d1b..89e8232b6e53 100644
--- a/src/ui/public/agg_types/buckets/create_filter/date_range.js
+++ b/src/ui/public/agg_types/buckets/create_filter/date_range.js
@@ -4,9 +4,9 @@ import buildRangeFilter from 'ui/filter_manager/lib/range';
 export default function createDateRangeFilterProvider(config) {
 
   return function (agg, key) {
-    var range = dateRange.parse(key, config.get('dateFormat'));
+    let range = dateRange.parse(key, config.get('dateFormat'));
 
-    var filter = {};
+    let filter = {};
     if (range.from) filter.gte = +range.from;
     if (range.to) filter.lt = +range.to;
     if (range.to && range.from) filter.format = 'epoch_millis';
diff --git a/src/ui/public/agg_types/buckets/create_filter/filters.js b/src/ui/public/agg_types/buckets/create_filter/filters.js
index 60409405af00..e9cbde979f2f 100644
--- a/src/ui/public/agg_types/buckets/create_filter/filters.js
+++ b/src/ui/public/agg_types/buckets/create_filter/filters.js
@@ -3,8 +3,8 @@ import _ from 'lodash';
 export default function CreateFilterFiltersProvider(Private) {
   return function (aggConfig, key) {
     // have the aggConfig write agg dsl params
-    var dslFilters = _.get(aggConfig.toDsl(), 'filters.filters');
-    var filter = dslFilters[key];
+    let dslFilters = _.get(aggConfig.toDsl(), 'filters.filters');
+    let filter = dslFilters[key];
 
     if (filter) {
       return buildQueryFilter(filter.query, aggConfig.vis.indexPattern.id);
diff --git a/src/ui/public/agg_types/buckets/create_filter/histogram.js b/src/ui/public/agg_types/buckets/create_filter/histogram.js
index 250bebbeae23..0bc21c35010f 100644
--- a/src/ui/public/agg_types/buckets/create_filter/histogram.js
+++ b/src/ui/public/agg_types/buckets/create_filter/histogram.js
@@ -2,7 +2,7 @@ import buildRangeFilter from 'ui/filter_manager/lib/range';
 
 export default function createHistogramFitlerProvider(Private) {
   return function (aggConfig, key) {
-    var value = parseInt(key, 10);
+    let value = parseInt(key, 10);
 
     return buildRangeFilter(
       aggConfig.params.field,
diff --git a/src/ui/public/agg_types/buckets/create_filter/ip_range.js b/src/ui/public/agg_types/buckets/create_filter/ip_range.js
index 490f67b320e0..ea5efa64adc3 100644
--- a/src/ui/public/agg_types/buckets/create_filter/ip_range.js
+++ b/src/ui/public/agg_types/buckets/create_filter/ip_range.js
@@ -6,7 +6,7 @@ export default function createIpRangeFilterProvider() {
     if (aggConfig.params.ipRangeType === 'mask') {
       range = new CidrMask(key).getRange();
     } else {
-      var addresses = key.split(/\-/);
+      let addresses = key.split(/\-/);
       range = {
         from: addresses[0],
         to: addresses[1]
diff --git a/src/ui/public/agg_types/buckets/date_histogram.js b/src/ui/public/agg_types/buckets/date_histogram.js
index 0b252b262fdf..a939b94abe1f 100644
--- a/src/ui/public/agg_types/buckets/date_histogram.js
+++ b/src/ui/public/agg_types/buckets/date_histogram.js
@@ -10,17 +10,17 @@ import AggTypesBucketsIntervalOptionsProvider from 'ui/agg_types/buckets/_interv
 import ConfigDefaultsProvider from 'ui/config/defaults';
 import intervalTemplate from 'ui/agg_types/controls/interval.html';
 export default function DateHistogramAggType(timefilter, config, Private) {
-  var BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  var TimeBuckets = Private(TimeBucketsProvider);
-  var createFilter = Private(AggTypesBucketsCreateFilterDateHistogramProvider);
-  var intervalOptions = Private(AggTypesBucketsIntervalOptionsProvider);
-  var configDefaults = Private(ConfigDefaultsProvider);
+  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  let TimeBuckets = Private(TimeBucketsProvider);
+  let createFilter = Private(AggTypesBucketsCreateFilterDateHistogramProvider);
+  let intervalOptions = Private(AggTypesBucketsIntervalOptionsProvider);
+  let configDefaults = Private(ConfigDefaultsProvider);
 
-  var detectedTimezone = tzDetect.determine().name();
-  var tzOffset = moment().format('Z');
+  let detectedTimezone = tzDetect.determine().name();
+  let tzOffset = moment().format('Z');
 
   function getInterval(agg) {
-    var interval = _.get(agg, ['params', 'interval']);
+    let interval = _.get(agg, ['params', 'interval']);
     if (interval && interval.val === 'custom') interval = _.get(agg, ['params', 'customInterval']);
     return interval;
   }
@@ -39,8 +39,8 @@ export default function DateHistogramAggType(timefilter, config, Private) {
       date: true
     },
     makeLabel: function (agg) {
-      var output = this.params.write(agg);
-      var params = output.params;
+      let output = this.params.write(agg);
+      let params = output.params;
       return params.field + ' per ' + (output.metricScaleText || output.bucketInterval.description);
     },
     createFilter: createFilter,
@@ -81,7 +81,7 @@ export default function DateHistogramAggType(timefilter, config, Private) {
         name: 'interval',
         type: 'optioned',
         deserialize: function (state) {
-          var interval = _.find(intervalOptions, {val: state});
+          let interval = _.find(intervalOptions, {val: state});
           return interval || _.find(intervalOptions, function (option) {
             // For upgrading from 4.0.x to 4.1.x - intervals are now stored as 'y' instead of 'year',
             // but this maps the old values to the new values
@@ -98,16 +98,16 @@ export default function DateHistogramAggType(timefilter, config, Private) {
           setBounds(agg);
           agg.buckets.setInterval(getInterval(agg));
 
-          var interval = agg.buckets.getInterval();
+          let interval = agg.buckets.getInterval();
           output.bucketInterval = interval;
           output.params.interval = interval.expression;
 
-          var isDefaultTimezone = config.get('dateFormat:tz') === configDefaults['dateFormat:tz'].value;
+          let isDefaultTimezone = config.get('dateFormat:tz') === configDefaults['dateFormat:tz'].value;
           output.params.time_zone = isDefaultTimezone ?
             (detectedTimezone || tzOffset) :
             config.get('dateFormat:tz');
 
-          var scaleMetrics = interval.scaled && interval.scale < 1;
+          let scaleMetrics = interval.scaled && interval.scale < 1;
           if (scaleMetrics) {
             scaleMetrics = _.every(agg.vis.aggs.bySchemaGroup.metrics, function (agg) {
               return agg.type && (agg.type.name === 'count' || agg.type.name === 'sum');
@@ -140,7 +140,7 @@ export default function DateHistogramAggType(timefilter, config, Private) {
         name: 'extended_bounds',
         default: {},
         write: function (agg, output) {
-          var val = agg.params.extended_bounds;
+          let val = agg.params.extended_bounds;
 
           if (val.min != null || val.max != null) {
             output.params.extended_bounds = {
diff --git a/src/ui/public/agg_types/buckets/date_range.js b/src/ui/public/agg_types/buckets/date_range.js
index e36047cab88c..1101cc72b439 100644
--- a/src/ui/public/agg_types/buckets/date_range.js
+++ b/src/ui/public/agg_types/buckets/date_range.js
@@ -7,9 +7,9 @@ import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 import dateRangesTemplate from 'ui/agg_types/controls/date_ranges.html';
 
 export default function DateRangeAggDefinition(Private, config) {
-  var BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  var createFilter = Private(AggTypesBucketsCreateFilterDateRangeProvider);
-  var fieldFormats = Private(RegistryFieldFormatsProvider);
+  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  let createFilter = Private(AggTypesBucketsCreateFilterDateRangeProvider);
+  let fieldFormats = Private(RegistryFieldFormatsProvider);
 
 
   return new BucketAggType({
@@ -17,7 +17,7 @@ export default function DateRangeAggDefinition(Private, config) {
     title: 'Date Range',
     createFilter: createFilter,
     getKey: function (bucket, key, agg) {
-      var formatter = agg.fieldOwnFormatter('text', fieldFormats.getDefaultInstance('date'));
+      let formatter = agg.fieldOwnFormatter('text', fieldFormats.getDefaultInstance('date'));
       return dateRange.toString(bucket, formatter);
     },
     getFormat: function () {
diff --git a/src/ui/public/agg_types/buckets/filters.js b/src/ui/public/agg_types/buckets/filters.js
index af54504c8fa3..47ab9c13bd0c 100644
--- a/src/ui/public/agg_types/buckets/filters.js
+++ b/src/ui/public/agg_types/buckets/filters.js
@@ -5,10 +5,10 @@ import AggTypesBucketsCreateFilterFiltersProvider from 'ui/agg_types/buckets/cre
 import DecorateQueryProvider from 'ui/courier/data_source/_decorate_query';
 import filtersTemplate from 'ui/agg_types/controls/filters.html';
 export default function FiltersAggDefinition(Private, Notifier) {
-  var BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  var createFilter = Private(AggTypesBucketsCreateFilterFiltersProvider);
-  var decorateQuery = Private(DecorateQueryProvider);
-  var notif = new Notifier({ location: 'Filters Agg' });
+  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  let createFilter = Private(AggTypesBucketsCreateFilterFiltersProvider);
+  let decorateQuery = Private(DecorateQueryProvider);
+  let notif = new Notifier({ location: 'Filters Agg' });
 
   return new BucketAggType({
     name: 'filters',
@@ -21,25 +21,25 @@ export default function FiltersAggDefinition(Private, Notifier) {
         editor: filtersTemplate,
         default: [ {input: {}, label: ''} ],
         write: function (aggConfig, output) {
-          var inFilters = aggConfig.params.filters;
+          let inFilters = aggConfig.params.filters;
           if (!_.size(inFilters)) return;
 
-          var outFilters = _.transform(inFilters, function (filters, filter) {
-            var input = filter.input;
+          let outFilters = _.transform(inFilters, function (filters, filter) {
+            let input = filter.input;
             if (!input) return notif.log('malformed filter agg params, missing "input" query');
 
-            var query = input.query;
+            let query = input.query;
             if (!query) return notif.log('malformed filter agg params, missing "query" on input');
 
             decorateQuery(query);
 
-            var label = filter.label || _.get(query, 'query_string.query') || angular.toJson(query);
+            let label = filter.label || _.get(query, 'query_string.query') || angular.toJson(query);
             filters[label] = input;
           }, {});
 
           if (!_.size(outFilters)) return;
 
-          var params = output.params || (output.params = {});
+          let params = output.params || (output.params = {});
           params.filters = outFilters;
         }
       }
diff --git a/src/ui/public/agg_types/buckets/geo_hash.js b/src/ui/public/agg_types/buckets/geo_hash.js
index dcaaa1d17b79..d27d6bf338d8 100644
--- a/src/ui/public/agg_types/buckets/geo_hash.js
+++ b/src/ui/public/agg_types/buckets/geo_hash.js
@@ -3,11 +3,11 @@ import moment from 'moment';
 import AggTypesBucketsBucketAggTypeProvider from 'ui/agg_types/buckets/_bucket_agg_type';
 import precisionTemplate from 'ui/agg_types/controls/precision.html';
 export default function GeoHashAggDefinition(Private, config) {
-  var BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  var defaultPrecision = 2;
+  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  let defaultPrecision = 2;
 
   function getPrecision(precision) {
-    var maxPrecision = _.parseInt(config.get('visualization:tileMap:maxPrecision'));
+    let maxPrecision = _.parseInt(config.get('visualization:tileMap:maxPrecision'));
 
     precision = parseInt(precision, 10);
 
diff --git a/src/ui/public/agg_types/buckets/histogram.js b/src/ui/public/agg_types/buckets/histogram.js
index c580625793e8..bbfd761b1522 100644
--- a/src/ui/public/agg_types/buckets/histogram.js
+++ b/src/ui/public/agg_types/buckets/histogram.js
@@ -7,8 +7,8 @@ import intervalTemplate from 'ui/agg_types/controls/interval.html';
 import minDocCountTemplate from 'ui/agg_types/controls/min_doc_count.html';
 import extendedBoundsTemplate from 'ui/agg_types/controls/extended_bounds.html';
 export default function HistogramAggDefinition(Private) {
-  var BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  var createFilter = Private(AggTypesBucketsCreateFilterHistogramProvider);
+  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  let createFilter = Private(AggTypesBucketsCreateFilterHistogramProvider);
 
 
   return new BucketAggType({
@@ -49,7 +49,7 @@ export default function HistogramAggDefinition(Private) {
         default: {},
         editor: extendedBoundsTemplate,
         write: function (aggConfig, output) {
-          var val = aggConfig.params.extended_bounds;
+          let val = aggConfig.params.extended_bounds;
 
           if (aggConfig.params.min_doc_count && (val.min != null || val.max != null)) {
             output.params.extended_bounds = {
@@ -61,7 +61,7 @@ export default function HistogramAggDefinition(Private) {
 
         // called from the editor
         shouldShow: function (aggConfig) {
-          var field = aggConfig.params.field;
+          let field = aggConfig.params.field;
           if (
             field
             && (field.type === 'number' || field.type === 'date')
diff --git a/src/ui/public/agg_types/buckets/ip_range.js b/src/ui/public/agg_types/buckets/ip_range.js
index ea14437eb39e..ea1a44610162 100644
--- a/src/ui/public/agg_types/buckets/ip_range.js
+++ b/src/ui/public/agg_types/buckets/ip_range.js
@@ -6,8 +6,8 @@ import AggTypesBucketsCreateFilterIpRangeProvider from 'ui/agg_types/buckets/cre
 import ipRangesTemplate from 'ui/agg_types/controls/ip_ranges.html';
 
 export default function RangeAggDefinition(Private) {
-  var BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  var createFilter = Private(AggTypesBucketsCreateFilterIpRangeProvider);
+  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  let createFilter = Private(AggTypesBucketsCreateFilterIpRangeProvider);
 
   return new BucketAggType({
     name: 'ip_range',
@@ -38,7 +38,7 @@ export default function RangeAggDefinition(Private) {
         },
         editor: ipRangesTemplate,
         write: function (aggConfig, output) {
-          var ipRangeType = aggConfig.params.ipRangeType;
+          let ipRangeType = aggConfig.params.ipRangeType;
           output.params.ranges = aggConfig.params.ranges[ipRangeType];
         }
       }
diff --git a/src/ui/public/agg_types/buckets/range.js b/src/ui/public/agg_types/buckets/range.js
index bc57b997774d..ec6d33935b7c 100644
--- a/src/ui/public/agg_types/buckets/range.js
+++ b/src/ui/public/agg_types/buckets/range.js
@@ -5,13 +5,13 @@ import IndexPatternsFieldFormatFieldFormatProvider from 'ui/index_patterns/_fiel
 import RangeKeyProvider from './range_key';
 import rangesTemplate from 'ui/agg_types/controls/ranges.html';
 export default function RangeAggDefinition(Private) {
-  var BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  var createFilter = Private(AggTypesBucketsCreateFilterRangeProvider);
-  var FieldFormat = Private(IndexPatternsFieldFormatFieldFormatProvider);
-  var RangeKey = Private(RangeKeyProvider);
+  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  let createFilter = Private(AggTypesBucketsCreateFilterRangeProvider);
+  let FieldFormat = Private(IndexPatternsFieldFormatFieldFormatProvider);
+  let RangeKey = Private(RangeKeyProvider);
 
-  var keyCaches = new WeakMap();
-  var formats = new WeakMap();
+  let keyCaches = new WeakMap();
+  let formats = new WeakMap();
 
   return new BucketAggType({
     name: 'range',
@@ -21,14 +21,14 @@ export default function RangeAggDefinition(Private) {
       return aggConfig.params.field.displayName + ' ranges';
     },
     getKey: function (bucket, key, agg) {
-      var keys = keyCaches.get(agg);
+      let keys = keyCaches.get(agg);
 
       if (!keys) {
         keys = new Map();
         keyCaches.set(agg, keys);
       }
 
-      var id = RangeKey.idBucket(bucket);
+      let id = RangeKey.idBucket(bucket);
 
       key = keys.get(id);
       if (!key) {
diff --git a/src/ui/public/agg_types/buckets/significant_terms.js b/src/ui/public/agg_types/buckets/significant_terms.js
index ae924e6552b5..36fe87d970d8 100644
--- a/src/ui/public/agg_types/buckets/significant_terms.js
+++ b/src/ui/public/agg_types/buckets/significant_terms.js
@@ -3,8 +3,8 @@ import AggTypesBucketsBucketAggTypeProvider from 'ui/agg_types/buckets/_bucket_a
 import AggTypesBucketsCreateFilterTermsProvider from 'ui/agg_types/buckets/create_filter/terms';
 import orderAndSizeTemplate from 'ui/agg_types/controls/order_and_size.html';
 export default function SignificantTermsAggDefinition(Private) {
-  var BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  var createFilter = Private(AggTypesBucketsCreateFilterTermsProvider);
+  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  let createFilter = Private(AggTypesBucketsCreateFilterTermsProvider);
 
   return new BucketAggType({
     name: 'significant_terms',
diff --git a/src/ui/public/agg_types/buckets/terms.js b/src/ui/public/agg_types/buckets/terms.js
index acc74d7cf2f4..4a81cbbf939f 100644
--- a/src/ui/public/agg_types/buckets/terms.js
+++ b/src/ui/public/agg_types/buckets/terms.js
@@ -7,13 +7,13 @@ import AggTypesBucketsCreateFilterTermsProvider from 'ui/agg_types/buckets/creat
 import orderAggTemplate from 'ui/agg_types/controls/order_agg.html';
 import orderAndSizeTemplate from 'ui/agg_types/controls/order_and_size.html';
 export default function TermsAggDefinition(Private) {
-  var BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  var bucketCountBetween = Private(AggTypesBucketsBucketCountBetweenProvider);
-  var AggConfig = Private(VisAggConfigProvider);
-  var Schemas = Private(VisSchemasProvider);
-  var createFilter = Private(AggTypesBucketsCreateFilterTermsProvider);
+  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  let bucketCountBetween = Private(AggTypesBucketsBucketCountBetweenProvider);
+  let AggConfig = Private(VisAggConfigProvider);
+  let Schemas = Private(VisSchemasProvider);
+  let createFilter = Private(AggTypesBucketsCreateFilterTermsProvider);
 
-  var orderAggSchema = (new Schemas([
+  let orderAggSchema = (new Schemas([
     {
       group: 'none',
       name: 'orderAgg',
@@ -24,7 +24,7 @@ export default function TermsAggDefinition(Private) {
 
   function isNotType(type) {
     return function (agg) {
-      var field = agg.params.field;
+      let field = agg.params.field;
       return !field || field.type !== type;
     };
   }
@@ -33,7 +33,7 @@ export default function TermsAggDefinition(Private) {
     name: 'terms',
     title: 'Terms',
     makeLabel: function (agg) {
-      var params = agg.params;
+      let params = agg.params;
       return params.field.displayName + ': ' + params.order.display;
     },
     createFilter: createFilter,
@@ -73,7 +73,7 @@ export default function TermsAggDefinition(Private) {
         makeOrderAgg: function (termsAgg, state) {
           state = state || {};
           state.schema = orderAggSchema;
-          var orderAgg = new AggConfig(termsAgg.vis, state);
+          let orderAgg = new AggConfig(termsAgg.vis, state);
           orderAgg.id = termsAgg.id + '-orderAgg';
           return orderAgg;
         },
@@ -86,18 +86,18 @@ export default function TermsAggDefinition(Private) {
             }
           };
 
-          var INIT = {}; // flag to know when prevOrderBy has changed
-          var prevOrderBy = INIT;
+          let INIT = {}; // flag to know when prevOrderBy has changed
+          let prevOrderBy = INIT;
 
           $scope.$watch('responseValueAggs', updateOrderAgg);
           $scope.$watch('agg.params.orderBy', updateOrderAgg);
 
           function updateOrderAgg() {
-            var agg = $scope.agg;
-            var aggs = agg.vis.aggs;
-            var params = agg.params;
-            var orderBy = params.orderBy;
-            var paramDef = agg.type.params.byName.orderAgg;
+            let agg = $scope.agg;
+            let aggs = agg.vis.aggs;
+            let params = agg.params;
+            let orderBy = params.orderBy;
+            let paramDef = agg.type.params.byName.orderAgg;
 
             // setup the initial value of orderBy
             if (!orderBy && prevOrderBy === INIT) {
@@ -130,11 +130,11 @@ export default function TermsAggDefinition(Private) {
           }
         },
         write: function (agg, output) {
-          var vis = agg.vis;
-          var dir = agg.params.order.val;
-          var order = output.params.order = {};
+          let vis = agg.vis;
+          let dir = agg.params.order.val;
+          let order = output.params.order = {};
 
-          var orderAgg = agg.params.orderAgg || vis.aggs.getResponseAggById(agg.params.orderBy);
+          let orderAgg = agg.params.orderAgg || vis.aggs.getResponseAggById(agg.params.orderBy);
 
           // TODO: This works around an Elasticsearch bug the always casts terms agg scripts to strings
           // thus causing issues with filtering. This probably causes other issues since float might not
@@ -153,7 +153,7 @@ export default function TermsAggDefinition(Private) {
             return;
           }
 
-          var orderAggId = orderAgg.id;
+          let orderAggId = orderAgg.id;
           if (orderAgg.parentId) {
             orderAgg = vis.aggs.byId[orderAgg.parentId];
           }
diff --git a/src/ui/public/agg_types/index.js b/src/ui/public/agg_types/index.js
index dafc04b8245a..762a9dbab4a9 100644
--- a/src/ui/public/agg_types/index.js
+++ b/src/ui/public/agg_types/index.js
@@ -21,7 +21,7 @@ import AggTypesBucketsSignificantTermsProvider from 'ui/agg_types/buckets/signif
 import AggTypesBucketsGeoHashProvider from 'ui/agg_types/buckets/geo_hash';
 export default function AggTypeService(Private) {
 
-  var aggs = {
+  let aggs = {
     metrics: [
       Private(AggTypesMetricsCountProvider),
       Private(AggTypesMetricsAvgProvider),
diff --git a/src/ui/public/agg_types/metrics/avg.js b/src/ui/public/agg_types/metrics/avg.js
index e70c3b775408..f313464433da 100644
--- a/src/ui/public/agg_types/metrics/avg.js
+++ b/src/ui/public/agg_types/metrics/avg.js
@@ -1,7 +1,7 @@
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 
 export default function AggTypeMetricAvgProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
 
   return new MetricAggType({
     name: 'avg',
diff --git a/src/ui/public/agg_types/metrics/cardinality.js b/src/ui/public/agg_types/metrics/cardinality.js
index 0cce5b7ab1be..8ff6d93f6192 100644
--- a/src/ui/public/agg_types/metrics/cardinality.js
+++ b/src/ui/public/agg_types/metrics/cardinality.js
@@ -2,8 +2,8 @@ import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_ag
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 
 export default function AggTypeMetricCardinalityProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  var fieldFormats = Private(RegistryFieldFormatsProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let fieldFormats = Private(RegistryFieldFormatsProvider);
 
   return new MetricAggType({
     name: 'cardinality',
diff --git a/src/ui/public/agg_types/metrics/count.js b/src/ui/public/agg_types/metrics/count.js
index ec9d2d37008f..fcad3d8dffa0 100644
--- a/src/ui/public/agg_types/metrics/count.js
+++ b/src/ui/public/agg_types/metrics/count.js
@@ -2,8 +2,8 @@ import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_ag
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 
 export default function AggTypeMetricCountProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  var fieldFormats = Private(RegistryFieldFormatsProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let fieldFormats = Private(RegistryFieldFormatsProvider);
 
   return new MetricAggType({
     name: 'count',
diff --git a/src/ui/public/agg_types/metrics/get_response_agg_config_class.js b/src/ui/public/agg_types/metrics/get_response_agg_config_class.js
index b90a308e8686..b9112f343e81 100644
--- a/src/ui/public/agg_types/metrics/get_response_agg_config_class.js
+++ b/src/ui/public/agg_types/metrics/get_response_agg_config_class.js
@@ -30,7 +30,7 @@ export default function ResponseAggConfigProvider() {
       this.key = key;
       this.parentId = this.id;
 
-      var subId = String(key);
+      let subId = String(key);
       if (subId.indexOf('.') > -1) {
         this.id = this.parentId + '[\'' + subId.replace(/'/g, '\\\'') + '\']';
       } else {
diff --git a/src/ui/public/agg_types/metrics/max.js b/src/ui/public/agg_types/metrics/max.js
index 70e893f0b869..938ee8d4a45e 100644
--- a/src/ui/public/agg_types/metrics/max.js
+++ b/src/ui/public/agg_types/metrics/max.js
@@ -1,7 +1,7 @@
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 
 export default function AggTypeMetricMaxProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
 
   return new MetricAggType({
     name: 'max',
diff --git a/src/ui/public/agg_types/metrics/median.js b/src/ui/public/agg_types/metrics/median.js
index 1f6273e1def5..dad3c9b9bd30 100644
--- a/src/ui/public/agg_types/metrics/median.js
+++ b/src/ui/public/agg_types/metrics/median.js
@@ -3,9 +3,9 @@ import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_ag
 import AggTypesMetricsGetResponseAggConfigClassProvider from 'ui/agg_types/metrics/get_response_agg_config_class';
 import AggTypesMetricsPercentilesProvider from 'ui/agg_types/metrics/percentiles';
 export default function AggTypeMetricMaxProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  var getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
-  var percentiles = Private(AggTypesMetricsPercentilesProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
+  let percentiles = Private(AggTypesMetricsPercentilesProvider);
 
   return new MetricAggType({
     name: 'median',
diff --git a/src/ui/public/agg_types/metrics/metric_agg_type.js b/src/ui/public/agg_types/metrics/metric_agg_type.js
index 1d435accefe3..e9d03f60f335 100644
--- a/src/ui/public/agg_types/metrics/metric_agg_type.js
+++ b/src/ui/public/agg_types/metrics/metric_agg_type.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 import AggTypesAggTypeProvider from 'ui/agg_types/agg_type';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 export default function MetricAggTypeProvider(Private) {
-  var AggType = Private(AggTypesAggTypeProvider);
-  var fieldFormats = Private(RegistryFieldFormatsProvider);
+  let AggType = Private(AggTypesAggTypeProvider);
+  let fieldFormats = Private(RegistryFieldFormatsProvider);
 
   _.class(MetricAggType).inherits(AggType);
   function MetricAggType(config) {
@@ -24,7 +24,7 @@ export default function MetricAggTypeProvider(Private) {
    */
   MetricAggType.prototype.getValue = function (agg, bucket) {
     // Metric types where an empty set equals `zero`
-    var isSettableToZero = ['cardinality', 'sum'].indexOf(agg.__type.name) !== -1;
+    let isSettableToZero = ['cardinality', 'sum'].indexOf(agg.__type.name) !== -1;
 
     // Return proper values when no buckets are present
     // `Count` handles empty sets properly
@@ -42,7 +42,7 @@ export default function MetricAggTypeProvider(Private) {
    * @return {FieldFromat}
    */
   MetricAggType.prototype.getFormat = function (agg) {
-    var field = agg.field();
+    let field = agg.field();
     return field ? field.format : fieldFormats.getDefaultInstance('number');
   };
 
diff --git a/src/ui/public/agg_types/metrics/min.js b/src/ui/public/agg_types/metrics/min.js
index fd31dbd3dff5..a14593af1dd0 100644
--- a/src/ui/public/agg_types/metrics/min.js
+++ b/src/ui/public/agg_types/metrics/min.js
@@ -1,7 +1,7 @@
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 
 export default function AggTypeMetricMinProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
 
   return new MetricAggType({
     name: 'min',
diff --git a/src/ui/public/agg_types/metrics/percentile_ranks.js b/src/ui/public/agg_types/metrics/percentile_ranks.js
index f0e6147a6c70..0ddc449a05ed 100644
--- a/src/ui/public/agg_types/metrics/percentile_ranks.js
+++ b/src/ui/public/agg_types/metrics/percentile_ranks.js
@@ -7,16 +7,16 @@ import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 import getPercentileValue from './percentiles_get_value';
 
 export default function AggTypeMetricPercentileRanksProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  var getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
-  var fieldFormats = Private(RegistryFieldFormatsProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
+  let fieldFormats = Private(RegistryFieldFormatsProvider);
 
   // required by the values editor
 
-  var valueProps = {
+  let valueProps = {
     makeLabel: function () {
-      var field = this.field();
-      var format = (field && field.format) || fieldFormats.getDefaultInstance('number');
+      let field = this.field();
+      let format = (field && field.format) || fieldFormats.getDefaultInstance('number');
 
       return 'Percentile rank ' + format.convert(this.key, 'text') + ' of "' + this.fieldDisplayName() + '"';
     }
@@ -45,7 +45,7 @@ export default function AggTypeMetricPercentileRanksProvider(Private) {
       }
     ],
     getResponseAggs: function (agg) {
-      var ValueAggConfig = getResponseAggConfigClass(agg, valueProps);
+      let ValueAggConfig = getResponseAggConfigClass(agg, valueProps);
 
       return agg.params.values.map(function (value) {
         return new ValueAggConfig(value);
diff --git a/src/ui/public/agg_types/metrics/percentiles.js b/src/ui/public/agg_types/metrics/percentiles.js
index 08edbfc193a8..d14401143e7c 100644
--- a/src/ui/public/agg_types/metrics/percentiles.js
+++ b/src/ui/public/agg_types/metrics/percentiles.js
@@ -8,13 +8,13 @@ import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 import getPercentileValue from './percentiles_get_value';
 
 export default function AggTypeMetricPercentilesProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  var getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
-  var fieldFormats = Private(RegistryFieldFormatsProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
+  let fieldFormats = Private(RegistryFieldFormatsProvider);
 
   // required by the percentiles editor
 
-  var valueProps = {
+  let valueProps = {
     makeLabel: function () {
       return ordinalSuffix(this.key) + ' percentile of ' + this.fieldDisplayName();
     }
@@ -43,7 +43,7 @@ export default function AggTypeMetricPercentilesProvider(Private) {
       }
     ],
     getResponseAggs: function (agg) {
-      var ValueAggConfig = getResponseAggConfigClass(agg, valueProps);
+      let ValueAggConfig = getResponseAggConfigClass(agg, valueProps);
 
       return agg.params.percents.map(function (percent) {
         return new ValueAggConfig(percent);
diff --git a/src/ui/public/agg_types/metrics/std_deviation.js b/src/ui/public/agg_types/metrics/std_deviation.js
index 7114a666fea8..36340ee4fbc6 100644
--- a/src/ui/public/agg_types/metrics/std_deviation.js
+++ b/src/ui/public/agg_types/metrics/std_deviation.js
@@ -2,16 +2,16 @@ import _ from 'lodash';
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 import AggTypesMetricsGetResponseAggConfigClassProvider from 'ui/agg_types/metrics/get_response_agg_config_class';
 export default function AggTypeMetricStandardDeviationProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  var getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
 
-  var responseAggConfigProps = {
+  let responseAggConfigProps = {
     valProp: function () {
-      var details = this.keyedDetails(this.params.customLabel)[this.key];
+      let details = this.keyedDetails(this.params.customLabel)[this.key];
       return details.valProp;
     },
     makeLabel: function () {
-      var details = this.keyedDetails(this.params.customLabel)[this.key];
+      let details = this.keyedDetails(this.params.customLabel)[this.key];
       return details.title + ' of ' + this.fieldDisplayName();
     },
     keyedDetails: function (customLabel) {
@@ -48,7 +48,7 @@ export default function AggTypeMetricStandardDeviationProvider(Private) {
     ],
 
     getResponseAggs: function (agg) {
-      var ValueAggConfig = getResponseAggConfigClass(agg, responseAggConfigProps);
+      let ValueAggConfig = getResponseAggConfigClass(agg, responseAggConfigProps);
 
       return [
         new ValueAggConfig('std_lower'),
diff --git a/src/ui/public/agg_types/metrics/sum.js b/src/ui/public/agg_types/metrics/sum.js
index cbdced241db1..d419edb241e6 100644
--- a/src/ui/public/agg_types/metrics/sum.js
+++ b/src/ui/public/agg_types/metrics/sum.js
@@ -1,7 +1,7 @@
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 
 export default function AggTypeMetricSumProvider(Private) {
-  var MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
 
   return new MetricAggType({
     name: 'sum',
diff --git a/src/ui/public/agg_types/param_types/field.js b/src/ui/public/agg_types/param_types/field.js
index 7cd72f27141c..9a6fc8b36964 100644
--- a/src/ui/public/agg_types/param_types/field.js
+++ b/src/ui/public/agg_types/param_types/field.js
@@ -4,7 +4,7 @@ import editorHtml from 'ui/agg_types/controls/field.html';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function FieldAggParamFactory(Private) {
 
-  var BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(FieldAggParam).inherits(BaseAggParam);
   function FieldAggParam(config) {
@@ -33,7 +33,7 @@ export default function FieldAggParamFactory(Private) {
    * @return {field}
    */
   FieldAggParam.prototype.deserialize = function (fieldName, aggConfig) {
-    var field = aggConfig.vis.indexPattern.fields.byName[fieldName];
+    let field = aggConfig.vis.indexPattern.fields.byName[fieldName];
 
     if (!field) {
       throw new SavedObjectNotFound('index-pattern-field', fieldName);
@@ -53,7 +53,7 @@ export default function FieldAggParamFactory(Private) {
    * @return {undefined}
    */
   FieldAggParam.prototype.write = function (aggConfig, output) {
-    var field = aggConfig.params.field;
+    let field = aggConfig.params.field;
 
     if (field.scripted) {
       output.params.script = {
diff --git a/src/ui/public/agg_types/param_types/optioned.js b/src/ui/public/agg_types/param_types/optioned.js
index 646d7c103b55..2e161a879a6c 100644
--- a/src/ui/public/agg_types/param_types/optioned.js
+++ b/src/ui/public/agg_types/param_types/optioned.js
@@ -3,7 +3,7 @@ import IndexedArray from 'ui/indexed_array';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function OptionedAggParamFactory(Private) {
 
-  var BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(OptionedAggParam).inherits(BaseAggParam);
   function OptionedAggParam(config) {
diff --git a/src/ui/public/agg_types/param_types/raw_json.js b/src/ui/public/agg_types/param_types/raw_json.js
index 8cc22af5cdce..25f160174230 100644
--- a/src/ui/public/agg_types/param_types/raw_json.js
+++ b/src/ui/public/agg_types/param_types/raw_json.js
@@ -3,7 +3,7 @@ import editorHtml from 'ui/agg_types/controls/raw_json.html';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function RawJSONAggParamFactory(Private) {
 
-  var BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(RawJSONAggParam).inherits(BaseAggParam);
   function RawJSONAggParam(config) {
@@ -26,7 +26,7 @@ export default function RawJSONAggParamFactory(Private) {
    */
   RawJSONAggParam.prototype.write = function (aggConfig, output) {
     let paramJSON;
-    var param = aggConfig.params[this.name];
+    let param = aggConfig.params[this.name];
 
     if (!param) {
       return;
@@ -45,7 +45,7 @@ export default function RawJSONAggParamFactory(Private) {
         .keys()
         .union(_.keys(b))
         .transform(function (dest, key) {
-          var val = compare(a[key], b[key]);
+          let val = compare(a[key], b[key]);
           if (val !== undefined) dest[key] = val;
         }, {})
         .value();
diff --git a/src/ui/public/agg_types/param_types/regex.js b/src/ui/public/agg_types/param_types/regex.js
index 6268c0ef3c84..3a38c06f8b9d 100644
--- a/src/ui/public/agg_types/param_types/regex.js
+++ b/src/ui/public/agg_types/param_types/regex.js
@@ -3,7 +3,7 @@ import editorHtml from 'ui/agg_types/controls/regular_expression.html';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function RegexAggParamFactory(Private) {
 
-  var BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(RegexAggParam).inherits(BaseAggParam);
   function RegexAggParam(config) {
@@ -33,15 +33,15 @@ export default function RegexAggParamFactory(Private) {
    * @return {undefined}
    */
   RegexAggParam.prototype.write = function (aggConfig, output) {
-    var param = aggConfig.params[this.name];
-    var paramType = aggConfig.type.params.byName[this.name];
+    let param = aggConfig.params[this.name];
+    let paramType = aggConfig.type.params.byName[this.name];
 
     // clear aggParam if pattern is not set or is disabled
     if (!param || !param.pattern || !param.pattern.length || paramType.disabled(aggConfig)) {
       return;
     }
 
-    var obj = {
+    let obj = {
       pattern: param.pattern
     };
 
diff --git a/src/ui/public/agg_types/param_types/string.js b/src/ui/public/agg_types/param_types/string.js
index 8c3a1057d6fa..58803171c44a 100644
--- a/src/ui/public/agg_types/param_types/string.js
+++ b/src/ui/public/agg_types/param_types/string.js
@@ -3,7 +3,7 @@ import editorHtml from 'ui/agg_types/controls/string.html';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function FieldAggParamFactory(Private) {
 
-  var BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(ScriptAggParam).inherits(BaseAggParam);
   function ScriptAggParam(config) {
diff --git a/src/ui/public/bind/bind.js b/src/ui/public/bind/bind.js
index 000912c559d0..ba16ddc5bfdc 100644
--- a/src/ui/public/bind/bind.js
+++ b/src/ui/public/bind/bind.js
@@ -27,26 +27,26 @@ uiModules.get('kibana')
      * @return {undefined}
      */
     $delegate.constructor.prototype.$bind = function (to, from, $sourceScope) {
-      var $source = $sourceScope || this.$parent;
-      var $target = this;
+      let $source = $sourceScope || this.$parent;
+      let $target = this;
 
       // parse expressions
-      var $to = $parse(to);
+      let $to = $parse(to);
       if (!$to.assign) errorNotAssignable(to, from);
-      var $from = $parse(from);
+      let $from = $parse(from);
 
       // bind scopes to expressions
-      var getTarget = function () { return $to($target); };
-      var setTarget = function (v) { return $to.assign($target, v); };
-      var getSource = function () { return $from($source); };
-      var setSource = function (v) { return $from.assignOrFail($source, v); };
+      let getTarget = function () { return $to($target); };
+      let setTarget = function (v) { return $to.assign($target, v); };
+      let getSource = function () { return $from($source); };
+      let setSource = function (v) { return $from.assignOrFail($source, v); };
 
       // to support writing from the child to the parent we need to know
       // which source has changed. Track the source value and anytime it
       // changes (even if the target value changed too) push from source
       // to target. If the source hasn't changed then the change is from
       // the target and push accordingly
-      var lastSourceVal = getSource();
+      let lastSourceVal = getSource();
 
       $from.assignOrFail = $from.assign || function () {
         // revert the change and throw an error, child writes aren't supported
@@ -55,19 +55,19 @@ uiModules.get('kibana')
       };
 
       // if we are syncing down a literal, then we use loose equality check
-      var strict = !$from.literal;
-      var compare = strict ? strictEquality : angular.equals;
+      let strict = !$from.literal;
+      let compare = strict ? strictEquality : angular.equals;
 
 
       // push the initial value down, start off in sync
       setTarget(lastSourceVal);
 
       $target.$watch(function () {
-        var sourceVal = getSource();
-        var targetVal = getTarget();
+        let sourceVal = getSource();
+        let targetVal = getTarget();
 
-        var outOfSync = !compare(sourceVal, targetVal);
-        var sourceChanged = outOfSync && !compare(sourceVal, lastSourceVal);
+        let outOfSync = !compare(sourceVal, targetVal);
+        let sourceChanged = outOfSync && !compare(sourceVal, lastSourceVal);
 
         if (sourceChanged) setTarget(sourceVal);
         else if (outOfSync) setSource(targetVal);
diff --git a/src/ui/public/chrome/api/angular.js b/src/ui/public/chrome/api/angular.js
index 2561cdfcc92e..587c327758fb 100644
--- a/src/ui/public/chrome/api/angular.js
+++ b/src/ui/public/chrome/api/angular.js
@@ -7,7 +7,7 @@ module.exports = function (chrome, internals) {
   chrome.getBreadcrumbs = _.noop;
 
   chrome.setupAngular = function () {
-    var kibana = modules.get('kibana');
+    let kibana = modules.get('kibana');
 
     _.forOwn(chrome.getInjected(), function (val, name) {
       kibana.value(name, val);
@@ -21,7 +21,7 @@ module.exports = function (chrome, internals) {
     .value('sessionId', Date.now())
     .value('chrome', chrome)
     .value('esUrl', (function () {
-      var a = document.createElement('a');
+      let a = document.createElement('a');
       a.href = chrome.addBasePath('/elasticsearch');
       return a.href;
     }()))
diff --git a/src/ui/public/chrome/api/controls.js b/src/ui/public/chrome/api/controls.js
index 38b1136ea87a..93408b9c682d 100644
--- a/src/ui/public/chrome/api/controls.js
+++ b/src/ui/public/chrome/api/controls.js
@@ -10,7 +10,7 @@ module.exports = function (chrome, internals) {
    *     determines if the Kibana chrome should be displayed
    */
 
-  var def = true;
+  let def = true;
   internals.setVisibleDefault = (_def) => def = Boolean(_def);
 
   /**
diff --git a/src/ui/public/chrome/api/nav.js b/src/ui/public/chrome/api/nav.js
index 0a3611c47c8d..73a2396510d3 100644
--- a/src/ui/public/chrome/api/nav.js
+++ b/src/ui/public/chrome/api/nav.js
@@ -11,10 +11,10 @@ export default function (chrome, internals) {
   };
 
   chrome.addBasePath = function (url) {
-    var isUrl = url && isString(url);
+    let isUrl = url && isString(url);
     if (!isUrl) return url;
 
-    var parsed = parse(url, true);
+    let parsed = parse(url, true);
     if (!parsed.host && parsed.pathname) {
       if (parsed.pathname[0] === '/') {
         parsed.pathname = chrome.getBasePath() + parsed.pathname;
@@ -111,7 +111,7 @@ export default function (chrome, internals) {
 
   internals.nav.forEach(link => {
     // convert all link urls to absolute urls
-    var a = document.createElement('a');
+    let a = document.createElement('a');
     a.setAttribute('href', link.url);
     link.url = a.href;
   });
diff --git a/src/ui/public/chrome/api/tabs.js b/src/ui/public/chrome/api/tabs.js
index c7ac25e14ce2..aba3734cfd1c 100644
--- a/src/ui/public/chrome/api/tabs.js
+++ b/src/ui/public/chrome/api/tabs.js
@@ -85,7 +85,7 @@ module.exports = function (chrome, internals) {
   // create a getter for properties of the active tab
   function activeGetter(prop) {
     return function (def) {
-      var active = chrome.getActiveTab();
+      let active = chrome.getActiveTab();
       return !active ? def : active[prop];
     };
   }
diff --git a/src/ui/public/chrome/api/theme.js b/src/ui/public/chrome/api/theme.js
index dba1bdbcecbb..192239cd9148 100644
--- a/src/ui/public/chrome/api/theme.js
+++ b/src/ui/public/chrome/api/theme.js
@@ -66,7 +66,7 @@ module.exports = function (chrome, internals) {
    * @return {chrome}
    */
   chrome.addApplicationClass = function (val) {
-    var classes = internals.applicationClasses || [];
+    let classes = internals.applicationClasses || [];
     classes.push(val);
     classes = _.uniq(classes);
 
@@ -81,8 +81,8 @@ module.exports = function (chrome, internals) {
    * @return {chrome}
    */
   chrome.removeApplicationClass = function (val) {
-    var classesToRemove = [].concat(val || []);
-    var classes = internals.applicationClasses || [];
+    let classesToRemove = [].concat(val || []);
+    let classes = internals.applicationClasses || [];
     _.pull(classes, ...classesToRemove);
 
     internals.applicationClasses = classes;
diff --git a/src/ui/public/chrome/chrome.js b/src/ui/public/chrome/chrome.js
index 7b2482b1ff29..c0f980c993b0 100644
--- a/src/ui/public/chrome/chrome.js
+++ b/src/ui/public/chrome/chrome.js
@@ -12,8 +12,8 @@ import 'ui/promises';
 import 'ui/directives/kbn_src';
 import 'ui/watch_multi';
 
-var chrome = {};
-var internals = _.defaults(
+let chrome = {};
+let internals = _.defaults(
   _.cloneDeep(metadata),
   {
     basePath: '',
diff --git a/src/ui/public/chrome/tab_collection.js b/src/ui/public/chrome/tab_collection.js
index d74e0104d33b..67759bb7e0d8 100644
--- a/src/ui/public/chrome/tab_collection.js
+++ b/src/ui/public/chrome/tab_collection.js
@@ -4,10 +4,10 @@ import { startsWith, get, set, omit, wrap, pick } from 'lodash';
 import { parse } from 'url';
 
 function TabCollection(opts = {}) {
-  var tabs = [];
-  var specs = null;
-  var defaults = opts.defaults || {};
-  var activeTab = null;
+  let tabs = [];
+  let specs = null;
+  let defaults = opts.defaults || {};
+  let activeTab = null;
 
   this.set = function (_specs) {
     specs = _.cloneDeep([].concat(_specs || []));
diff --git a/src/ui/public/collapsible_sidebar/collapsible_sidebar.js b/src/ui/public/collapsible_sidebar/collapsible_sidebar.js
index 4b3fc520e03c..d19a70af9643 100644
--- a/src/ui/public/collapsible_sidebar/collapsible_sidebar.js
+++ b/src/ui/public/collapsible_sidebar/collapsible_sidebar.js
@@ -8,15 +8,15 @@ uiModules
 .get('kibana')
 .directive('collapsibleSidebar', function () {
   // simply a list of all of all of angulars .col-md-* classes except 12
-  var listOfWidthClasses = _.times(11, function (i) { return 'col-md-' + i; });
+  let listOfWidthClasses = _.times(11, function (i) { return 'col-md-' + i; });
 
   return {
     restrict: 'C',
     link: function ($scope, $elem) {
-      var $collapser = $('<div class="sidebar-collapser"><div class="chevron-cont"></div></div>');
-      var $siblings = $elem.siblings();
+      let $collapser = $('<div class="sidebar-collapser"><div class="chevron-cont"></div></div>');
+      let $siblings = $elem.siblings();
 
-      var siblingsClass = listOfWidthClasses.reduce(function (prev, className) {
+      let siblingsClass = listOfWidthClasses.reduce(function (prev, className) {
         if (prev) return prev;
         return $siblings.hasClass(className) && className;
       }, false);
diff --git a/src/ui/public/config/_delayed_updater.js b/src/ui/public/config/_delayed_updater.js
index 7997120e3373..89f08e4ca628 100644
--- a/src/ui/public/config/_delayed_updater.js
+++ b/src/ui/public/config/_delayed_updater.js
@@ -4,14 +4,14 @@ import ConfigValsProvider from 'ui/config/_vals';
 import Notifier from 'ui/notify/notifier';
 
 export default function DelayedUpdaterFactory(Private, $rootScope, Promise) {
-  var notify = new Notifier();
+  let notify = new Notifier();
 
-  var vals = Private(ConfigValsProvider);
+  let vals = Private(ConfigValsProvider);
 
   return function DelayedUpdater(doc) {
-    var updater = this;
-    var queue = [];
-    var log = {};
+    let updater = this;
+    let queue = [];
+    let log = {};
     let timer;
 
     updater.fire = function () {
@@ -23,8 +23,8 @@ export default function DelayedUpdaterFactory(Private, $rootScope, Promise) {
 
       let method;
       let body;
-      var updated = [];
-      var deleted = [];
+      let updated = [];
+      let deleted = [];
 
       // seperate the log into lists
       Object.keys(log).forEach(function (key) {
@@ -55,8 +55,8 @@ export default function DelayedUpdaterFactory(Private, $rootScope, Promise) {
     };
 
     updater.update = function (key, val, silentAndLocal) {
-      var newVal = val;
-      var oldVal = vals[key];
+      let newVal = val;
+      let oldVal = vals[key];
 
       if (angular.equals(newVal, oldVal)) {
         return Promise.resolve();
@@ -72,7 +72,7 @@ export default function DelayedUpdaterFactory(Private, $rootScope, Promise) {
 
       if (silentAndLocal) return Promise.resolve();
 
-      var defer = Promise.defer();
+      let defer = Promise.defer();
       queue.push(defer);
       notify.log('config change: ' + key + ': ' + oldVal + ' -> ' + newVal);
       $rootScope.$broadcast('change:config.' + key, newVal, oldVal);
diff --git a/src/ui/public/config/config.js b/src/ui/public/config/config.js
index 9291de9e0fc2..bcf497e80b2b 100644
--- a/src/ui/public/config/config.js
+++ b/src/ui/public/config/config.js
@@ -8,7 +8,7 @@ import uiRoutes from 'ui/routes';
 import uiModules from 'ui/modules';
 import Notifier from 'ui/notify/notifier';
 
-var module = uiModules.get('kibana/config');
+let module = uiModules.get('kibana/config');
 
 uiRoutes.addSetupWork(function (config) {
   return config.init();
@@ -16,13 +16,13 @@ uiRoutes.addSetupWork(function (config) {
 
 // service for delivering config variables to everywhere else
 module.service('config', function (Private, kbnVersion, kbnIndex, $rootScope, buildNum) {
-  var config = this;
+  let config = this;
 
-  var defaults = Private(ConfigDefaultsProvider);
-  var DelayedUpdater = Private(ConfigDelayedUpdaterProvider);
-  var vals = Private(ConfigValsProvider);
+  let defaults = Private(ConfigDefaultsProvider);
+  let DelayedUpdater = Private(ConfigDelayedUpdaterProvider);
+  let vals = Private(ConfigValsProvider);
 
-  var notify = new Notifier({
+  let notify = new Notifier({
     location: 'Config'
   });
 
@@ -30,8 +30,8 @@ module.service('config', function (Private, kbnVersion, kbnIndex, $rootScope, bu
   // update once it is requested by calling #set() or #clear().
   let updater;
 
-  var DocSource = Private(DocSourceProvider);
-  var doc = (new DocSource())
+  let DocSource = Private(DocSourceProvider);
+  let doc = (new DocSource())
     .index(kbnIndex)
     .type('config')
     .id(kbnVersion);
@@ -47,13 +47,13 @@ module.service('config', function (Private, kbnVersion, kbnIndex, $rootScope, bu
    * @return {Promise} - Resolved when the config loads initially
    */
   config.init = _.once(function () {
-    var complete = notify.lifecycle('config init');
+    let complete = notify.lifecycle('config init');
 
     return (function getDoc() {
 
       // used to apply an entire es response to the vals, silentAndLocal will prevent
       // event/notifications/writes from occuring.
-      var applyMassUpdate = function (resp, silentAndLocal) {
+      let applyMassUpdate = function (resp, silentAndLocal) {
         _.union(_.keys(resp._source), _.keys(vals)).forEach(function (key) {
           change(key, resp._source[key], silentAndLocal);
         });
@@ -132,7 +132,7 @@ module.service('config', function (Private, kbnVersion, kbnIndex, $rootScope, bu
   config.$bind = function ($scope, key, property) {
     if (!property) property = key;
 
-    var update = function () {
+    let update = function () {
       $scope[property] = config.get(key);
     };
 
diff --git a/src/ui/public/courier/_redirect_when_missing.js b/src/ui/public/courier/_redirect_when_missing.js
index b6a17ac90d2d..b86c75cba412 100644
--- a/src/ui/public/courier/_redirect_when_missing.js
+++ b/src/ui/public/courier/_redirect_when_missing.js
@@ -1,9 +1,9 @@
 import errors from 'ui/errors';
 
 export default function RedirectWhenMissingFn($location, kbnUrl, Notifier, Promise) {
-  var SavedObjectNotFound = errors.SavedObjectNotFound;
+  let SavedObjectNotFound = errors.SavedObjectNotFound;
 
-  var notify = new Notifier();
+  let notify = new Notifier();
 
   /**
    * Creates an error handler that will redirect to a url when a SavedObjectNotFound
@@ -22,7 +22,7 @@ export default function RedirectWhenMissingFn($location, kbnUrl, Notifier, Promi
       // if this error is not "404", rethrow
       if (!(err instanceof SavedObjectNotFound)) throw err;
 
-      var url = mapping[err.savedObjectType] || mapping['*'];
+      let url = mapping[err.savedObjectType] || mapping['*'];
       if (!url) url = '/';
 
       url += (url.indexOf('?') >= 0 ? '&' : '?') + `notFound=${err.savedObjectType}`;
diff --git a/src/ui/public/courier/_request_queue.js b/src/ui/public/courier/_request_queue.js
index a5b940ec7c2b..b6dba26b187f 100644
--- a/src/ui/public/courier/_request_queue.js
+++ b/src/ui/public/courier/_request_queue.js
@@ -6,7 +6,7 @@ export default function PendingRequestList() {
    * they are processed by fetch.[sourceType]().
    * @type {Array}
    */
-  var queue = [];
+  let queue = [];
 
   queue.getInactive = function (/* strategies */) {
     return queue.get.apply(queue, arguments)
@@ -21,7 +21,7 @@ export default function PendingRequestList() {
 
   queue.get = function (...strategies) {
     return queue.filter(function (req) {
-      var strategyMatch = !strategies.length;
+      let strategyMatch = !strategies.length;
       if (!strategyMatch) {
         strategyMatch = strategies.some(function (strategy) {
           return req.strategy === strategy;
diff --git a/src/ui/public/courier/courier.js b/src/ui/public/courier/courier.js
index 486d5bcb20e8..4e09d24a8ef8 100644
--- a/src/ui/public/courier/courier.js
+++ b/src/ui/public/courier/courier.js
@@ -24,18 +24,18 @@ import RedirectWhenMissingProvider from './_redirect_when_missing';
 uiModules.get('kibana/courier')
 .service('courier', function ($rootScope, Private, Promise, indexPatterns) {
   function Courier() {
-    var self = this;
+    let self = this;
 
-    var DocSource = Private(DocSourceProvider);
-    var SearchSource = Private(SearchSourceProvider);
-    var searchStrategy = Private(SearchStrategyProvider);
+    let DocSource = Private(DocSourceProvider);
+    let SearchSource = Private(SearchSourceProvider);
+    let searchStrategy = Private(SearchStrategyProvider);
 
-    var requestQueue = Private(RequestQueueProvider);
-    var errorHandlers = Private(ErrorHandlersProvider);
+    let requestQueue = Private(RequestQueueProvider);
+    let errorHandlers = Private(ErrorHandlersProvider);
 
-    var fetch = Private(FetchProvider);
-    var docLooper = self.docLooper = Private(DocLooperProvider);
-    var searchLooper = self.searchLooper = Private(SearchLooperProvider);
+    let fetch = Private(FetchProvider);
+    let docLooper = self.docLooper = Private(DocLooperProvider);
+    let searchLooper = self.searchLooper = Private(SearchLooperProvider);
 
     // expose some internal modules
     self.setRootSearchSource = Private(RootSearchSourceProvider).set;
@@ -47,7 +47,7 @@ uiModules.get('kibana/courier')
     self.DocSource = DocSource;
     self.SearchSource = SearchSource;
 
-    var HastyRefresh = errors.HastyRefresh;
+    let HastyRefresh = errors.HastyRefresh;
 
     /**
      * update the time between automatic search requests
@@ -135,8 +135,8 @@ uiModules.get('kibana/courier')
 
     // Listen for refreshInterval changes
     $rootScope.$watchCollection('timefilter.refreshInterval', function () {
-      var refreshValue = _.get($rootScope, 'timefilter.refreshInterval.value');
-      var refreshPause = _.get($rootScope, 'timefilter.refreshInterval.pause');
+      let refreshValue = _.get($rootScope, 'timefilter.refreshInterval.value');
+      let refreshPause = _.get($rootScope, 'timefilter.refreshInterval.pause');
       if (_.isNumber(refreshValue) && !refreshPause) {
         self.fetchInterval(refreshValue);
       } else {
@@ -144,7 +144,7 @@ uiModules.get('kibana/courier')
       }
     });
 
-    var onFatalDefer = Promise.defer();
+    let onFatalDefer = Promise.defer();
     onFatalDefer.promise.then(self.close);
     Notifier.fatalCallbacks.push(onFatalDefer.resolve);
   }
diff --git a/src/ui/public/courier/data_source/_abstract.js b/src/ui/public/courier/data_source/_abstract.js
index d666db7ff5c5..07f6d856b52b 100644
--- a/src/ui/public/courier/data_source/_abstract.js
+++ b/src/ui/public/courier/data_source/_abstract.js
@@ -9,12 +9,12 @@ import FetchProvider from '../fetch';
 import DecorateQueryProvider from './_decorate_query';
 
 export default function SourceAbstractFactory(Private, Promise, PromiseEmitter) {
-  var requestQueue = Private(RequestQueueProvider);
-  var errorHandlers = Private(ErrorHandlersProvider);
-  var courierFetch = Private(FetchProvider);
+  let requestQueue = Private(RequestQueueProvider);
+  let errorHandlers = Private(ErrorHandlersProvider);
+  let courierFetch = Private(FetchProvider);
 
   function SourceAbstract(initialState, strategy) {
-    var self = this;
+    let self = this;
     self._instanceid = _.uniqueId('data_source');
 
     self._state = (function () {
@@ -57,7 +57,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    * @return {any} - the value found
    */
   SourceAbstract.prototype.get = function (name) {
-    var self = this;
+    let self = this;
     while (self) {
       if (self._state[name] !== void 0) return self._state[name];
       self = self.getParent();
@@ -79,7 +79,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    *   string of the state value to set
    */
   SourceAbstract.prototype.set = function (state, val) {
-    var self = this;
+    let self = this;
 
     if (typeof state === 'string') {
       // the getter and setter methods check for undefined explicitly
@@ -125,7 +125,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    * @return {Promise}
    */
   SourceAbstract.prototype.onResults = function (handler) {
-    var self = this;
+    let self = this;
 
     return new PromiseEmitter(function (resolve, reject) {
       const defer = Promise.defer();
@@ -149,7 +149,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    * @return {Promise}
    */
   SourceAbstract.prototype.onError = function (handler) {
-    var self = this;
+    let self = this;
 
     return new PromiseEmitter(function (resolve, reject) {
       const defer = Promise.defer();
@@ -172,8 +172,8 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    * @async
    */
   SourceAbstract.prototype.fetch = function () {
-    var self = this;
-    var req = _.first(self._myStartableQueued());
+    let self = this;
+    let req = _.first(self._myStartableQueued());
 
     if (!req) {
       req = self._createRequest();
@@ -232,16 +232,16 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    * @resolved {Object|null} - the flat state of the SourceAbstract
    */
   SourceAbstract.prototype._flatten = function () {
-    var type = this._getType();
+    let type = this._getType();
 
     // the merged state of this dataSource and it's ancestors
-    var flatState = {};
+    let flatState = {};
 
     // function used to write each property from each state object in the chain to flat state
-    var root = this;
+    let root = this;
 
     // start the chain at this source
-    var current = this;
+    let current = this;
 
     // call the ittr and return it's promise
     return (function ittr() {
@@ -255,12 +255,12 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
           });
         }
 
-        var prom = root._mergeProp(flatState, value, key);
+        let prom = root._mergeProp(flatState, value, key);
         return Promise.is(prom) ? prom : null;
       }))
       .then(function () {
         // move to this sources parent
-        var parent = current.getParent();
+        let parent = current.getParent();
         // keep calling until we reach the top parent
         if (parent) {
           current = parent;
@@ -271,7 +271,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
     .then(function () {
       if (type === 'search') {
         // This is down here to prevent the circular dependency
-        var decorateQuery = Private(DecorateQueryProvider);
+        let decorateQuery = Private(DecorateQueryProvider);
 
         flatState.body = flatState.body || {};
 
@@ -283,7 +283,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
         }
 
         if (flatState.body.size > 0) {
-          var computedFields = flatState.index.getComputedFields();
+          let computedFields = flatState.index.getComputedFields();
           flatState.body.fields = computedFields.fields;
           flatState.body.script_fields = flatState.body.script_fields || {};
           flatState.body.fielddata_fields = flatState.body.fielddata_fields || [];
@@ -301,7 +301,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
          *                          through otherwise it will filter out
          * @returns {function}
          */
-        var filterNegate = function (reverse) {
+        let filterNegate = function (reverse) {
           return function (filter) {
             if (_.isUndefined(filter.meta) || _.isUndefined(filter.meta.negate)) return !reverse;
             return filter.meta && filter.meta.negate === reverse;
@@ -313,7 +313,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
         * @param  {Object} filter - The fitler to translate
         * @return {Object} the query version of that filter
         */
-        var translateToQuery = function (filter) {
+        let translateToQuery = function (filter) {
           if (!filter) return;
 
           if (filter.query) {
@@ -328,7 +328,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
          * @param {object} filter The filter to clean
          * @returns {object}
          */
-        var cleanFilter = function (filter) {
+        let cleanFilter = function (filter) {
           return _.omit(filter, ['meta']);
         };
 
diff --git a/src/ui/public/courier/data_source/_decorate_query.js b/src/ui/public/courier/data_source/_decorate_query.js
index a97740b0508b..bb6fca29200b 100644
--- a/src/ui/public/courier/data_source/_decorate_query.js
+++ b/src/ui/public/courier/data_source/_decorate_query.js
@@ -7,7 +7,7 @@ export default function DecorateQuery(config) {
    * @returns {object}
    */
   return function (query) {
-    var queryOptions = config.get('query:queryString:options');
+    let queryOptions = config.get('query:queryString:options');
 
     if (_.has(query, 'query_string.query')) {
       _.extend(query.query_string, queryOptions);
diff --git a/src/ui/public/courier/data_source/_doc_send_to_es.js b/src/ui/public/courier/data_source/_doc_send_to_es.js
index ac2aea1e9c4c..5cc07f9e0425 100644
--- a/src/ui/public/courier/data_source/_doc_send_to_es.js
+++ b/src/ui/public/courier/data_source/_doc_send_to_es.js
@@ -5,8 +5,8 @@ import RequestQueueProvider from 'ui/courier/_request_queue';
 import FetchProvider from 'ui/courier/fetch/fetch';
 
 export default function (Promise, Private, es) {
-  var requestQueue = Private(RequestQueueProvider);
-  var courierFetch = Private(FetchProvider);
+  let requestQueue = Private(RequestQueueProvider);
+  let courierFetch = Private(FetchProvider);
 
   /**
    * Backend for doUpdate and doIndex
@@ -16,9 +16,9 @@ export default function (Promise, Private, es) {
    * @param  {String} body - HTTP request body
    */
   return function (method, validateVersion, body, ignore) {
-    var doc = this;
+    let doc = this;
     // straight assignment will causes undefined values
-    var params = _.pick(this._state, ['id', 'type', 'index']);
+    let params = _.pick(this._state, ['id', 'type', 'index']);
     params.body = body;
     params.ignore = ignore || [409];
 
@@ -51,13 +51,13 @@ export default function (Promise, Private, es) {
       // notify pending request for this same document that we have updates
       docFetchProm.then(function (fetchResp) {
         // use the key to compair sources
-        var key = doc._versionKey();
+        let key = doc._versionKey();
 
         // clear the queue and filter out the removed items, pushing the
         // unmatched ones back in.
-        var respondTo = requestQueue.splice(0).filter(function (req) {
-          var isDoc = req.source._getType() === 'doc';
-          var keyMatches = isDoc && req.source._versionKey() === key;
+        let respondTo = requestQueue.splice(0).filter(function (req) {
+          let isDoc = req.source._getType() === 'doc';
+          let keyMatches = isDoc && req.source._versionKey() === key;
 
           // put some request back into the queue
           if (!keyMatches) {
diff --git a/src/ui/public/courier/data_source/_normalize_sort_request.js b/src/ui/public/courier/data_source/_normalize_sort_request.js
index 1ea2eff0e36d..3798b0abd71d 100644
--- a/src/ui/public/courier/data_source/_normalize_sort_request.js
+++ b/src/ui/public/courier/data_source/_normalize_sort_request.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 
 export default function normalizeSortRequest(config) {
-  var defaultSortOptions = config.get('sort:options');
+  let defaultSortOptions = config.get('sort:options');
 
   /**
    * Decorate queries with default parameters
@@ -9,7 +9,7 @@ export default function normalizeSortRequest(config) {
    * @returns {object}
    */
   return function (sortObject, indexPattern) {
-    var normalizedSort = [];
+    let normalizedSort = [];
 
     // [].concat({}) -> [{}], [].concat([{}]) -> [{}]
     return [].concat(sortObject).map(function (sortable) {
@@ -22,10 +22,10 @@ export default function normalizeSortRequest(config) {
     { someField: "desc" } into { someField: { "order": "desc"}}
   */
   function normalize(sortable, indexPattern) {
-    var normalized = {};
-    var sortField = _.keys(sortable)[0];
-    var sortValue = sortable[sortField];
-    var indexField = indexPattern.fields.byName[sortField];
+    let normalized = {};
+    let sortField = _.keys(sortable)[0];
+    let sortValue = sortable[sortField];
+    let indexField = indexPattern.fields.byName[sortField];
 
     if (indexField && indexField.scripted && indexField.sortable) {
       let direction;
diff --git a/src/ui/public/courier/data_source/_root_search_source.js b/src/ui/public/courier/data_source/_root_search_source.js
index 045dc0611c3c..c3cb53ffb33c 100644
--- a/src/ui/public/courier/data_source/_root_search_source.js
+++ b/src/ui/public/courier/data_source/_root_search_source.js
@@ -1,11 +1,11 @@
 import SearchSourceProvider from 'ui/courier/data_source/search_source';
 
 export default function RootSearchSource(Private, $rootScope, timefilter, Notifier) {
-  var SearchSource = Private(SearchSourceProvider);
+  let SearchSource = Private(SearchSourceProvider);
 
-  var notify = new Notifier({ location: 'Root Search Source' });
+  let notify = new Notifier({ location: 'Root Search Source' });
 
-  var globalSource = new SearchSource();
+  let globalSource = new SearchSource();
   globalSource.inherits(false); // this is the final source, it has no parents
   globalSource.filter(function (globalSource) {
     // dynamic time filter will be called in the _flatten phase of things
@@ -35,7 +35,7 @@ export default function RootSearchSource(Private, $rootScope, timefilter, Notifi
 
     // walk the parent chain until we get to the global source or nothing
     // that's where we will attach to the globalSource
-    var literalRoot = source;
+    let literalRoot = source;
     while (literalRoot._parent && literalRoot._parent !== globalSource) {
       literalRoot = literalRoot._parent;
     }
diff --git a/src/ui/public/courier/data_source/doc_source.js b/src/ui/public/courier/data_source/doc_source.js
index c2725309bfb7..67d6de7e9e6b 100644
--- a/src/ui/public/courier/data_source/doc_source.js
+++ b/src/ui/public/courier/data_source/doc_source.js
@@ -9,10 +9,10 @@ import DocRequestProvider from '../fetch/request/doc';
 import DocStrategyProvider from '../fetch/strategy/doc';
 
 export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
-  var sendToEs = Private(DocSendToEsProvider);
-  var SourceAbstract = Private(AbstractDataSourceProvider);
-  var DocRequest = Private(DocRequestProvider);
-  var docStrategy = Private(DocStrategyProvider);
+  let sendToEs = Private(DocSendToEsProvider);
+  let SourceAbstract = Private(AbstractDataSourceProvider);
+  let DocRequest = Private(DocRequestProvider);
+  let docStrategy = Private(DocStrategyProvider);
 
   _.class(DocSource).inherits(SourceAbstract);
   function DocSource(initialState) {
@@ -99,7 +99,7 @@ export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
    * @return {string}
    */
   DocSource.prototype._versionKey = function () {
-    var state = this._state;
+    let state = this._state;
 
     if (!state.index || !state.type || !state.id) return;
     return 'DocVersion:' + (
@@ -125,10 +125,10 @@ export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
    * @return {[type]} [description]
    */
   DocSource.prototype._getStoredVersion = function () {
-    var key = this._versionKey();
+    let key = this._versionKey();
     if (!key) return;
 
-    var v = sessionStorage.get(key);
+    let v = sessionStorage.get(key);
     this._version = v ? _.parseInt(v) : void 0;
     return this._version;
   };
@@ -141,7 +141,7 @@ export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
   DocSource.prototype._storeVersion = function (version) {
     if (!version) return this._clearVersion();
 
-    var key = this._versionKey();
+    let key = this._versionKey();
     if (!key) return;
     this._version = version;
     sessionStorage.set(key, version);
@@ -151,7 +151,7 @@ export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
    * Clears the stored version for a DocSource
    */
   DocSource.prototype._clearVersion = function () {
-    var key = this._versionKey();
+    let key = this._versionKey();
     if (!key) return;
     sessionStorage.remove(key);
   };
diff --git a/src/ui/public/courier/data_source/search_source.js b/src/ui/public/courier/data_source/search_source.js
index 0cd2a14d749b..ef0fc31ab733 100644
--- a/src/ui/public/courier/data_source/search_source.js
+++ b/src/ui/public/courier/data_source/search_source.js
@@ -8,11 +8,11 @@ import SegmentedRequestProvider from '../fetch/request/segmented';
 import SearchStrategyProvider from '../fetch/strategy/search';
 
 export default function SearchSourceFactory(Promise, Private) {
-  var SourceAbstract = Private(AbstractDataSourceProvider);
-  var SearchRequest = Private(SearchRequestProvider);
-  var SegmentedRequest = Private(SegmentedRequestProvider);
-  var searchStrategy = Private(SearchStrategyProvider);
-  var normalizeSortRequest = Private(NormalizeSortRequestProvider);
+  let SourceAbstract = Private(AbstractDataSourceProvider);
+  let SearchRequest = Private(SearchRequestProvider);
+  let SegmentedRequest = Private(SegmentedRequestProvider);
+  let searchStrategy = Private(SearchStrategyProvider);
+  let normalizeSortRequest = Private(NormalizeSortRequestProvider);
 
   _.class(SearchSource).inherits(SourceAbstract);
   function SearchSource(initialState) {
@@ -71,7 +71,7 @@ export default function SearchSourceFactory(Promise, Private) {
    * @return {undefined|searchSource}
    */
   SearchSource.prototype.getParent = function (onlyHardLinked) {
-    var self = this;
+    let self = this;
     if (self._parent === false) return;
     if (self._parent) return self._parent;
     return onlyHardLinked ? undefined : Private(rootSearchSource).get();
@@ -92,9 +92,9 @@ export default function SearchSourceFactory(Promise, Private) {
   };
 
   SearchSource.prototype.onBeginSegmentedFetch = function (initFunction) {
-    var self = this;
+    let self = this;
     return Promise.try(function addRequest() {
-      var req = new SegmentedRequest(self, Promise.defer(), initFunction);
+      let req = new SegmentedRequest(self, Promise.defer(), initFunction);
 
       // return promises created by the completion handler so that
       // errors will bubble properly
@@ -139,7 +139,7 @@ export default function SearchSourceFactory(Promise, Private) {
    */
   SearchSource.prototype._mergeProp = function (state, val, key) {
     if (typeof val === 'function') {
-      var source = this;
+      let source = this;
       return Promise.cast(val(this))
       .then(function (newVal) {
         return source._mergeProp(state, newVal, key);
diff --git a/src/ui/public/courier/looper/_looper.js b/src/ui/public/courier/looper/_looper.js
index fcb25511e6a1..8ebf2df44d49 100644
--- a/src/ui/public/courier/looper/_looper.js
+++ b/src/ui/public/courier/looper/_looper.js
@@ -4,7 +4,7 @@ import 'ui/promises';
 import Notifier from 'ui/notify/notifier';
 
 export default function LooperFactory($timeout, Promise) {
-  var notify = new Notifier();
+  let notify = new Notifier();
 
   function Looper(ms, fn) {
     this._fn = fn;
@@ -130,7 +130,7 @@ export default function LooperFactory($timeout, Promise) {
    * @return {undefined}
    */
   Looper.prototype._loopTheLoop = function () {
-    var self = this;
+    let self = this;
 
     if (self.active) {
       self.onHastyLoop();
diff --git a/src/ui/public/courier/looper/doc.js b/src/ui/public/courier/looper/doc.js
index a1c6104ce20a..e0f21394777c 100644
--- a/src/ui/public/courier/looper/doc.js
+++ b/src/ui/public/courier/looper/doc.js
@@ -3,15 +3,15 @@ import LooperProvider from './_looper';
 import DocStrategyProvider from '../fetch/strategy/doc';
 
 export default function DocLooperService(Private) {
-  var fetch = Private(FetchProvider);
-  var Looper = Private(LooperProvider);
-  var DocStrategy = Private(DocStrategyProvider);
+  let fetch = Private(FetchProvider);
+  let Looper = Private(LooperProvider);
+  let DocStrategy = Private(DocStrategyProvider);
 
   /**
    * The Looper which will manage the doc fetch interval
    * @type {Looper}
    */
-  var docLooper = new Looper(1500, function () {
+  let docLooper = new Looper(1500, function () {
     fetch.fetchQueued(DocStrategy);
   });
 
diff --git a/src/ui/public/courier/looper/search.js b/src/ui/public/courier/looper/search.js
index cb3914c601c0..ae6867f77d50 100644
--- a/src/ui/public/courier/looper/search.js
+++ b/src/ui/public/courier/looper/search.js
@@ -4,18 +4,18 @@ import RequestQueueProvider from '../_request_queue';
 import LooperProvider from './_looper';
 
 export default function SearchLooperService(Private, Promise, Notifier, $rootScope) {
-  var fetch = Private(FetchProvider);
-  var searchStrategy = Private(SearchStrategyProvider);
-  var requestQueue = Private(RequestQueueProvider);
+  let fetch = Private(FetchProvider);
+  let searchStrategy = Private(SearchStrategyProvider);
+  let requestQueue = Private(RequestQueueProvider);
 
-  var Looper = Private(LooperProvider);
-  var notif = new Notifier({ location: 'Search Looper' });
+  let Looper = Private(LooperProvider);
+  let notif = new Notifier({ location: 'Search Looper' });
 
   /**
    * The Looper which will manage the doc fetch interval
    * @type {Looper}
    */
-  var searchLooper = new Looper(null, function () {
+  let searchLooper = new Looper(null, function () {
     $rootScope.$broadcast('courier:searchRefresh');
     return fetch.these(
       requestQueue.getInactive(searchStrategy)
diff --git a/src/ui/public/courier/saved_object/saved_object.js b/src/ui/public/courier/saved_object/saved_object.js
index 477c6c76b959..5c32ccac9064 100644
--- a/src/ui/public/courier/saved_object/saved_object.js
+++ b/src/ui/public/courier/saved_object/saved_object.js
@@ -10,38 +10,38 @@ import SearchSourceProvider from '../data_source/search_source';
 
 export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notifier, safeConfirm, indexPatterns) {
 
-  var DocSource = Private(DocSourceProvider);
-  var SearchSource = Private(SearchSourceProvider);
-  var mappingSetup = Private(MappingSetupProvider);
+  let DocSource = Private(DocSourceProvider);
+  let SearchSource = Private(SearchSourceProvider);
+  let mappingSetup = Private(MappingSetupProvider);
 
   function SavedObject(config) {
     if (!_.isObject(config)) config = {};
 
     // save an easy reference to this
-    var self = this;
+    let self = this;
 
     /************
      * Initialize config vars
      ************/
     // the doc which is used to store this object
-    var docSource = new DocSource();
+    let docSource = new DocSource();
 
     // type name for this object, used as the ES-type
-    var type = config.type;
+    let type = config.type;
 
     // Create a notifier for sending alerts
-    var notify = new Notifier({
+    let notify = new Notifier({
       location: 'Saved ' + type
     });
 
     // mapping definition for the fields that this object will expose
-    var mapping = mappingSetup.expandShorthand(config.mapping);
+    let mapping = mappingSetup.expandShorthand(config.mapping);
 
     // default field values, assigned when the source is loaded
-    var defaults = config.defaults || {};
+    let defaults = config.defaults || {};
 
-    var afterESResp = config.afterESResp || _.noop;
-    var customInit = config.init || _.noop;
+    let afterESResp = config.afterESResp || _.noop;
+    let customInit = config.init || _.noop;
 
     // optional search source which this object configures
     self.searchSource = config.searchSource && new SearchSource();
@@ -113,7 +113,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
 
       if (resp.found != null && !resp.found) throw new errors.SavedObjectNotFound(type, self.id);
 
-      var meta = resp._source.kibanaSavedObjectMeta || {};
+      let meta = resp._source.kibanaSavedObjectMeta || {};
       delete resp._source.kibanaSavedObjectMeta;
 
       if (!config.indexPattern && self._source.indexPattern) {
@@ -158,8 +158,8 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
         state = {};
       }
 
-      var oldState = self.searchSource.toJSON();
-      var fnProps = _.transform(oldState, function (dynamic, val, name) {
+      let oldState = self.searchSource.toJSON();
+      let fnProps = _.transform(oldState, function (dynamic, val, name) {
         if (_.isFunction(val)) dynamic[name] = val;
       }, {});
 
@@ -176,7 +176,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
       return Promise.try(function () {
         if (self.searchSource) {
 
-          var index = config.indexPattern || self.searchSource.getOwn('index');
+          let index = config.indexPattern || self.searchSource.getOwn('index');
           if (!index) return;
           if (config.clearSavedIndexPattern) {
             self.searchSource.set('index', undefined);
@@ -200,7 +200,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
      * @return {Object}
      */
     self.serialize = function () {
-      var body = {};
+      let body = {};
 
       _.forOwn(mapping, function (fieldMapping, fieldName) {
         if (self[fieldName] != null) {
@@ -227,7 +227,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
      */
     self.save = function () {
 
-      var body = self.serialize();
+      let body = self.serialize();
 
       // Slugify the object id
       self.id = slugifyId(self.id);
@@ -240,7 +240,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
     };
 
     self.saveSource = function (source) {
-      var finish = function (id) {
+      let finish = function (id) {
         self.id = id;
         return es.indices.refresh({
           index: kbnIndex
@@ -255,7 +255,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
       .catch(function (err) {
         // record exists, confirm overwriting
         if (_.get(err, 'origError.status') === 409) {
-          var confirmMessage = 'Are you sure you want to overwrite ' + self.title + '?';
+          let confirmMessage = 'Are you sure you want to overwrite ' + self.title + '?';
 
           return safeConfirm(confirmMessage).then(
             function () {
diff --git a/src/ui/public/debounce/debounce.js b/src/ui/public/debounce/debounce.js
index f317ee51b85c..7f8652f39d8f 100644
--- a/src/ui/public/debounce/debounce.js
+++ b/src/ui/public/debounce/debounce.js
@@ -3,7 +3,7 @@ import uiModules from 'ui/modules';
 // Debounce service, angularized version of lodash debounce
 // borrowed heavily from https://github.com/shahata/angular-debounce
 
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.service('debounce', ['$timeout', function ($timeout) {
   return function (func, wait, options) {
@@ -20,14 +20,14 @@ module.service('debounce', ['$timeout', function ($timeout) {
       self = this;
       args = arguments;
 
-      var later = function () {
+      let later = function () {
         timeout = null;
         if (!options.leading || options.trailing) {
           result = func.apply(self, args);
         }
       };
 
-      var callNow = options.leading && !timeout;
+      let callNow = options.leading && !timeout;
 
       if (timeout) {
         $timeout.cancel(timeout);
diff --git a/src/ui/public/directives/auto_select_if_only_one.js b/src/ui/public/directives/auto_select_if_only_one.js
index b5c96abae51b..2fead2be3983 100644
--- a/src/ui/public/directives/auto_select_if_only_one.js
+++ b/src/ui/public/directives/auto_select_if_only_one.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('autoSelectIfOnlyOne', function ($parse) {
   return {
@@ -7,7 +7,7 @@ module.directive('autoSelectIfOnlyOne', function ($parse) {
     require: 'ngModel',
     link: function (scope, element, attributes, ngModelCtrl) {
       attributes.$observe('autoSelectIfOnlyOne', function (result) {
-        var options = $parse(result)(scope);
+        let options = $parse(result)(scope);
         if (options && options.length === 1) {
           ngModelCtrl.$setViewValue(options[0]);
           ngModelCtrl.$render();
diff --git a/src/ui/public/directives/bread_crumbs.js b/src/ui/public/directives/bread_crumbs.js
index f78739f098a5..145c2749f85a 100644
--- a/src/ui/public/directives/bread_crumbs.js
+++ b/src/ui/public/directives/bread_crumbs.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import chrome from 'ui/chrome/chrome';
 import breadCrumbsTemplate from 'ui/partials/bread_crumbs.html';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('breadCrumbs', function () {
   return {
diff --git a/src/ui/public/directives/click_focus.js b/src/ui/public/directives/click_focus.js
index 4f5353514370..5a005676699c 100644
--- a/src/ui/public/directives/click_focus.js
+++ b/src/ui/public/directives/click_focus.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import $ from 'jquery';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('clickFocus', function () {
   return {
@@ -11,7 +11,7 @@ module.directive('clickFocus', function () {
     restrict: 'A',
     link: function ($scope, $elem) {
       function handler() {
-        var focusElem = $.find('input[name=' + $scope.clickFocus + ']');
+        let focusElem = $.find('input[name=' + $scope.clickFocus + ']');
         if (focusElem[0]) focusElem[0].focus();
       }
 
diff --git a/src/ui/public/directives/confirm_click.js b/src/ui/public/directives/confirm_click.js
index 027facb56b17..9c83e861ee29 100644
--- a/src/ui/public/directives/confirm_click.js
+++ b/src/ui/public/directives/confirm_click.js
@@ -6,9 +6,9 @@ uiModules
     restrict: 'A',
     link: function ($scope, $elem, attrs) {
       $elem.bind('click', function () {
-        var message = attrs.confirmation || 'Are you sure?';
+        let message = attrs.confirmation || 'Are you sure?';
         if (window.confirm(message)) { // eslint-disable-line no-alert
-          var action = attrs.confirmClick;
+          let action = attrs.confirmClick;
           if (action) {
             $scope.$apply($scope.$eval(action));
           }
diff --git a/src/ui/public/directives/css_truncate.js b/src/ui/public/directives/css_truncate.js
index bebff1a1fa92..b9541a814d2d 100644
--- a/src/ui/public/directives/css_truncate.js
+++ b/src/ui/public/directives/css_truncate.js
@@ -1,7 +1,7 @@
 import $ from 'jquery';
 import _ from 'lodash';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('cssTruncate', function ($timeout) {
   return {
diff --git a/src/ui/public/directives/field_name.js b/src/ui/public/directives/field_name.js
index d167958f56c2..22944b50019a 100644
--- a/src/ui/public/directives/field_name.js
+++ b/src/ui/public/directives/field_name.js
@@ -1,6 +1,6 @@
 import 'ui/filters/short_dots';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('fieldName', function ($compile, $rootScope, $filter) {
   return {
@@ -12,7 +12,7 @@ module.directive('fieldName', function ($compile, $rootScope, $filter) {
     },
     link: function ($scope, $el) {
 
-      var typeIcon = function (fieldType) {
+      let typeIcon = function (fieldType) {
         switch (fieldType) {
           case 'source':
             return '<i title="source" class="fa fa-file-text-o "></i>';
@@ -44,12 +44,12 @@ module.directive('fieldName', function ($compile, $rootScope, $filter) {
         'field.rowCount'
       ], function () {
 
-        var type = $scope.field ? $scope.field.type : $scope.fieldType;
-        var name = $scope.field ? $scope.field.name : $scope.fieldName;
-        var results = $scope.field ? !$scope.field.rowCount && !$scope.field.scripted : false;
-        var scripted = $scope.field ? $scope.field.scripted : false;
+        let type = $scope.field ? $scope.field.type : $scope.fieldType;
+        let name = $scope.field ? $scope.field.name : $scope.fieldName;
+        let results = $scope.field ? !$scope.field.rowCount && !$scope.field.scripted : false;
+        let scripted = $scope.field ? $scope.field.scripted : false;
 
-        var displayName = $filter('shortDots')(name);
+        let displayName = $filter('shortDots')(name);
 
         $el
           .text(displayName)
diff --git a/src/ui/public/directives/file_upload.js b/src/ui/public/directives/file_upload.js
index fe2aaffc7715..2283f34319da 100644
--- a/src/ui/public/directives/file_upload.js
+++ b/src/ui/public/directives/file_upload.js
@@ -1,25 +1,25 @@
 import $ from 'jquery';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('fileUpload', function ($parse) {
   return {
     restrict: 'A',
     link: function ($scope, $elem, attrs) {
-      var onUpload = $parse(attrs.fileUpload);
+      let onUpload = $parse(attrs.fileUpload);
 
-      var $fileInput = $('<input type="file" style="opacity: 0" id="testfile" />');
+      let $fileInput = $('<input type="file" style="opacity: 0" id="testfile" />');
       $elem.after($fileInput);
 
       $fileInput.on('change', function (e) {
-        var reader = new FileReader();
+        let reader = new FileReader();
         reader.onload = function (e) {
           $scope.$apply(function () {
             onUpload($scope, {fileContents: e.target.result});
           });
         };
 
-        var target = e.srcElement || e.target;
+        let target = e.srcElement || e.target;
         if (target && target.files && target.files.length) reader.readAsText(target.files[0]);
       });
 
diff --git a/src/ui/public/directives/inequality.js b/src/ui/public/directives/inequality.js
index 67ed3aeb051d..b6e2ed72b068 100644
--- a/src/ui/public/directives/inequality.js
+++ b/src/ui/public/directives/inequality.js
@@ -5,8 +5,8 @@ function makeDirectiveDef(id, compare) {
     return {
       require: 'ngModel',
       link: function ($scope, $el, $attr, ngModel) {
-        var getBound = function () { return $parse($attr[id])(); };
-        var defaultVal = {
+        let getBound = function () { return $parse($attr[id])(); };
+        let defaultVal = {
           'greaterThan': -Infinity,
           'lessThan': Infinity
         }[id];
@@ -19,8 +19,8 @@ function makeDirectiveDef(id, compare) {
         });
 
         function validate(val) {
-          var bound = !isNaN(getBound()) ? +getBound() : defaultVal;
-          var valid = !isNaN(bound) && !isNaN(val) && compare(val, bound);
+          let bound = !isNaN(getBound()) ? +getBound() : defaultVal;
+          let valid = !isNaN(bound) && !isNaN(val) && compare(val, bound);
           ngModel.$setValidity(id, valid);
           return val;
         }
diff --git a/src/ui/public/directives/infinite_scroll.js b/src/ui/public/directives/infinite_scroll.js
index 50df93f06136..db1f410f56ed 100644
--- a/src/ui/public/directives/infinite_scroll.js
+++ b/src/ui/public/directives/infinite_scroll.js
@@ -1,6 +1,6 @@
 import $ from 'jquery';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('kbnInfiniteScroll', function () {
   return {
@@ -9,20 +9,20 @@ module.directive('kbnInfiniteScroll', function () {
       more: '='
     },
     link: function ($scope, $element, attrs) {
-      var $window = $(window);
+      let $window = $(window);
       let checkTimer;
 
       function onScroll() {
         if (!$scope.more) return;
 
-        var winHeight = $window.height();
-        var winBottom = winHeight + $window.scrollTop();
-        var elTop = $element.offset().top;
-        var remaining = elTop - winBottom;
+        let winHeight = $window.height();
+        let winBottom = winHeight + $window.scrollTop();
+        let elTop = $element.offset().top;
+        let remaining = elTop - winBottom;
 
         if (remaining <= winHeight * 0.50) {
           $scope[$scope.$$phase ? '$eval' : '$apply'](function () {
-            var more = $scope.more();
+            let more = $scope.more();
           });
         }
       }
diff --git a/src/ui/public/directives/input_datetime.js b/src/ui/public/directives/input_datetime.js
index 1e82ae790e87..0559358e8309 100644
--- a/src/ui/public/directives/input_datetime.js
+++ b/src/ui/public/directives/input_datetime.js
@@ -2,7 +2,7 @@ import $ from 'jquery';
 import _ from 'lodash';
 import moment from 'moment';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('inputDatetime', function () {
   return {
@@ -10,18 +10,18 @@ module.directive('inputDatetime', function () {
     require: 'ngModel',
     link: function ($scope, $elem, attrs, ngModel) {
 
-      var format = 'YYYY-MM-DD HH:mm:ss.SSS';
+      let format = 'YYYY-MM-DD HH:mm:ss.SSS';
 
       $elem.after('<div class="input-datetime-format">' + format + '</div>');
 
       // What should I make with the input from the user?
-      var fromUser = function (text) {
-        var parsed = moment(text, format);
+      let fromUser = function (text) {
+        let parsed = moment(text, format);
         return parsed.isValid() ? parsed : undefined;
       };
 
       // How should I present the data back to the user in the input field?
-      var toUser = function (datetime) {
+      let toUser = function (datetime) {
         return moment(datetime).format(format);
       };
 
diff --git a/src/ui/public/directives/input_focus.js b/src/ui/public/directives/input_focus.js
index f4484717f085..c6adccfd3e7b 100644
--- a/src/ui/public/directives/input_focus.js
+++ b/src/ui/public/directives/input_focus.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('inputFocus', function ($timeout) {
   return {
diff --git a/src/ui/public/directives/input_whole_number.js b/src/ui/public/directives/input_whole_number.js
index 11d388dfb889..5a4f406ea5a9 100644
--- a/src/ui/public/directives/input_whole_number.js
+++ b/src/ui/public/directives/input_whole_number.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('inputWholeNumber', function () {
   return {
diff --git a/src/ui/public/directives/json_input.js b/src/ui/public/directives/json_input.js
index 1b2e61a8eca1..640b5bd88790 100644
--- a/src/ui/public/directives/json_input.js
+++ b/src/ui/public/directives/json_input.js
@@ -15,7 +15,7 @@ uiModules
       function fromJSON(value) {
         try {
           value = JSON.parse(value);
-          var validity = !scope.$eval(attrs.requireKeys) ? true : _.keys(value).length > 0;
+          let validity = !scope.$eval(attrs.requireKeys) ? true : _.keys(value).length > 0;
           ngModelCntrl.$setValidity('json', validity);
         } catch (e) {
           ngModelCntrl.$setValidity('json', false);
diff --git a/src/ui/public/directives/paginate.js b/src/ui/public/directives/paginate.js
index 444df4b3f4b7..cf11e8ac6fd0 100644
--- a/src/ui/public/directives/paginate.js
+++ b/src/ui/public/directives/paginate.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import uiModules from 'ui/modules';
 import paginateControlsTemplate from 'ui/partials/paginate_controls.html';
 
-var PER_PAGE_DEFAULT = 10;
+let PER_PAGE_DEFAULT = 10;
 
 uiModules.get('kibana')
 .directive('paginate', function ($parse, $compile) {
@@ -22,7 +22,7 @@ uiModules.get('kibana')
           $el.prepend($compile('<paginate-controls class="paginate-top">')($scope));
         }
 
-        var paginate = $scope.paginate;
+        let paginate = $scope.paginate;
 
         // add some getters to the controller powered by attributes
         paginate.getList = $parse(attrs.list);
@@ -42,8 +42,8 @@ uiModules.get('kibana')
     },
     controllerAs: 'paginate',
     controller: function ($scope) {
-      var self = this;
-      var ALL = 0;
+      let self = this;
+      let ALL = 0;
 
       self.sizeOptions = [
         { title: '10', value: 10 },
@@ -62,8 +62,8 @@ uiModules.get('kibana')
           self.perPageProp,
           self.otherWidthGetter
         ], function (vals, oldVals) {
-          var intChanges = vals[0] !== oldVals[0];
-          var extChanges = vals[1] !== oldVals[1];
+          let intChanges = vals[0] !== oldVals[0];
+          let extChanges = vals[1] !== oldVals[1];
 
           if (intChanges) {
             if (!setPerPage(self.perPage)) {
@@ -102,14 +102,14 @@ uiModules.get('kibana')
         $scope.pages = [];
         if (!$scope.list) return;
 
-        var perPage = _.parseInt(self.perPage);
-        var count = perPage ? Math.ceil($scope.list.length / perPage) : 1;
+        let perPage = _.parseInt(self.perPage);
+        let count = perPage ? Math.ceil($scope.list.length / perPage) : 1;
 
         _.times(count, function (i) {
           let page;
 
           if (perPage) {
-            var start = perPage * i;
+            let start = perPage * i;
             page = $scope.list.slice(start, start + perPage);
           } else {
             page = $scope.list.slice(0);
@@ -144,9 +144,9 @@ uiModules.get('kibana')
 
         // setup the list of the other pages to link to
         $scope.otherPages = [];
-        var width = +self.otherWidthGetter($scope) || 5;
-        var left = page.i - Math.round((width - 1) / 2);
-        var right = left + width - 1;
+        let width = +self.otherWidthGetter($scope) || 5;
+        let left = page.i - Math.round((width - 1) / 2);
+        let right = left + width - 1;
 
         // shift neg count from left to right
         if (left < 0) {
@@ -155,14 +155,14 @@ uiModules.get('kibana')
         }
 
         // shift extra right nums to left
-        var lastI = page.count - 1;
+        let lastI = page.count - 1;
         if (right > lastI) {
           right = lastI;
           left = right - width + 1;
         }
 
-        for (var i = left; i <= right; i++) {
-          var other = $scope.pages[i];
+        for (let i = left; i <= right; i++) {
+          let other = $scope.pages[i];
 
           if (!other) continue;
 
@@ -173,7 +173,7 @@ uiModules.get('kibana')
       };
 
       function setPerPage(val) {
-        var $ppParent = $scope;
+        let $ppParent = $scope;
 
         while ($ppParent && !_.has($ppParent, self.perPageProp)) {
           $ppParent = $ppParent.$parent;
diff --git a/src/ui/public/directives/pretty_duration.js b/src/ui/public/directives/pretty_duration.js
index 79e5bc25c71d..80262b962605 100644
--- a/src/ui/public/directives/pretty_duration.js
+++ b/src/ui/public/directives/pretty_duration.js
@@ -4,7 +4,7 @@ import moment from 'moment';
 import 'ui/timepicker/quick_ranges';
 import 'ui/timepicker/time_units';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 
 module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
@@ -15,9 +15,9 @@ module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
       to: '='
     },
     link: function ($scope, $elem) {
-      var dateFormat = config.get('dateFormat');
+      let dateFormat = config.get('dateFormat');
 
-      var lookupByRange = {};
+      let lookupByRange = {};
       _.each(quickRanges, function (frame) {
         lookupByRange[frame.from + ' to ' + frame.to] = frame;
       });
@@ -26,13 +26,13 @@ module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
         let text;
         // If both parts are date math, try to look up a reasonable string
         if ($scope.from && $scope.to && !moment.isMoment($scope.from) && !moment.isMoment($scope.to)) {
-          var tryLookup = lookupByRange[$scope.from.toString() + ' to ' + $scope.to.toString()];
+          let tryLookup = lookupByRange[$scope.from.toString() + ' to ' + $scope.to.toString()];
           if (tryLookup) {
             $elem.text(tryLookup.display);
           } else {
-            var fromParts = $scope.from.toString().split('-');
+            let fromParts = $scope.from.toString().split('-');
             if ($scope.to.toString() === 'now' && fromParts[0] === 'now' && fromParts[1]) {
-              var rounded = fromParts[1].split('/');
+              let rounded = fromParts[1].split('/');
               text = 'Last ' + rounded[0];
               if (rounded[1]) {
                 text = text + ' rounded to the ' + timeUnits[rounded[1]];
@@ -49,7 +49,7 @@ module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
       };
 
       function cantLookup() {
-        var display = {};
+        let display = {};
         _.each(['from', 'to'], function (time) {
           if (moment.isMoment($scope[time])) {
             display[time] = $scope[time].format(dateFormat);
@@ -57,7 +57,7 @@ module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
             if ($scope[time] === 'now') {
               display[time] = 'now';
             } else {
-              var tryParse = dateMath.parse($scope[time], time === 'to' ? true : false);
+              let tryParse = dateMath.parse($scope[time], time === 'to' ? true : false);
               display[time] = moment.isMoment(tryParse) ? '~ ' + tryParse.fromNow() : $scope[time];
             }
           }
diff --git a/src/ui/public/directives/rows.js b/src/ui/public/directives/rows.js
index 436bfb983071..11f3ae3f2e96 100644
--- a/src/ui/public/directives/rows.js
+++ b/src/ui/public/directives/rows.js
@@ -3,24 +3,24 @@ import _ from 'lodash';
 import AggConfigResult from 'ui/vis/agg_config_result';
 import FilterBarFilterBarClickHandlerProvider from 'ui/filter_bar/filter_bar_click_handler';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('kbnRows', function ($compile, $rootScope, getAppState, Private) {
-  var filterBarClickHandler = Private(FilterBarFilterBarClickHandlerProvider);
+  let filterBarClickHandler = Private(FilterBarFilterBarClickHandlerProvider);
   return {
     restrict: 'A',
     link: function ($scope, $el, attr) {
       function addCell($tr, contents) {
-        var $cell = $(document.createElement('td'));
+        let $cell = $(document.createElement('td'));
 
         // TODO: It would be better to actually check the type of the field, but we don't have
         // access to it here. This may become a problem with the switch to BigNumber
         if (_.isNumeric(contents)) $cell.addClass('numeric-value');
 
-        var createAggConfigResultCell = function (aggConfigResult) {
-          var $cell = $(document.createElement('td'));
-          var $state = getAppState();
-          var clickHandler = filterBarClickHandler($state);
+        let createAggConfigResultCell = function (aggConfigResult) {
+          let $cell = $(document.createElement('td'));
+          let $state = getAppState();
+          let clickHandler = filterBarClickHandler($state);
           $cell.scope = $scope.$new();
           $cell.addClass('cell-hover');
           $cell.attr('ng-click', 'clickHandler($event)');
@@ -71,19 +71,19 @@ module.directive('kbnRows', function ($compile, $rootScope, getAppState, Private
         attr.kbnRows,
         attr.kbnRowsMin
       ], function (vals) {
-        var rows = vals[0];
-        var min = vals[1];
+        let rows = vals[0];
+        let min = vals[1];
 
         $el.empty();
 
         if (!_.isArray(rows)) rows = [];
-        var width = rows.reduce(maxRowSize, 0);
+        let width = rows.reduce(maxRowSize, 0);
 
         if (isFinite(min) && rows.length < min) {
           // clone the rows so that we can add elements to it without upsetting the original
           rows = _.clone(rows);
           // crate the empty row which will be pushed into the row list over and over
-          var emptyRow = new Array(width);
+          let emptyRow = new Array(width);
           // fill the empty row with values
           _.times(width, function (i) { emptyRow[i] = ''; });
           // push as many empty rows into the row array as needed
@@ -91,7 +91,7 @@ module.directive('kbnRows', function ($compile, $rootScope, getAppState, Private
         }
 
         rows.forEach(function (row) {
-          var $tr = $(document.createElement('tr')).appendTo($el);
+          let $tr = $(document.createElement('tr')).appendTo($el);
           row.forEach(function (cell) {
             addCell($tr, cell);
           });
diff --git a/src/ui/public/directives/saved_object_finder.js b/src/ui/public/directives/saved_object_finder.js
index becf923d5ee0..f6c7f766807e 100644
--- a/src/ui/public/directives/saved_object_finder.js
+++ b/src/ui/public/directives/saved_object_finder.js
@@ -4,11 +4,11 @@ import keymap from 'ui/utils/key_map';
 import SavedObjectsSavedObjectRegistryProvider from 'ui/saved_objects/saved_object_registry';
 import uiModules from 'ui/modules';
 import savedObjectFinderTemplate from 'ui/partials/saved_object_finder.html';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Private, config) {
 
-  var services = Private(SavedObjectsSavedObjectRegistryProvider).byLoaderPropertiesName;
+  let services = Private(SavedObjectsSavedObjectRegistryProvider).byLoaderPropertiesName;
 
   return {
     restrict: 'E',
@@ -23,19 +23,19 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
     template: savedObjectFinderTemplate,
     controllerAs: 'finder',
     controller: function ($scope, $element, $timeout) {
-      var self = this;
+      let self = this;
 
       // the text input element
-      var $input = $element.find('input[ng-model=filter]');
+      let $input = $element.find('input[ng-model=filter]');
 
       // The number of items to show in the list
       $scope.perPage = config.get('savedObjects:perPage');
 
       // the list that will hold the suggestions
-      var $list = $element.find('ul');
+      let $list = $element.find('ul');
 
       // the current filter string, used to check that returned results are still useful
-      var currentFilter = $scope.filter;
+      let currentFilter = $scope.filter;
 
       // the most recently entered search/filter
       let prevSearch;
@@ -95,7 +95,7 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
           $scope.userOnChoose(hit, $event);
         }
 
-        var url = self.makeUrl(hit);
+        let url = self.makeUrl(hit);
         if (!url || url === '#' || url.charAt(0) !== '#') return;
 
         $event.preventDefault();
@@ -133,7 +133,7 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
           case 'enter':
             if (self.hitCount !== 1) return;
 
-            var hit = self.hits[0];
+            let hit = self.hits[0];
             if (!hit) return;
 
             self.onChoose(hit, $event);
@@ -206,8 +206,8 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
           case 'enter':
             if (!self.selector.enabled) break;
 
-            var hitIndex = ((page.number - 1) * paginate.perPage) + self.selector.index;
-            var hit = self.hits[hitIndex];
+            let hitIndex = ((page.number - 1) * paginate.perPage) + self.selector.index;
+            let hit = self.hits[hitIndex];
             if (!hit) break;
 
             self.onChoose(hit, $event);
@@ -249,7 +249,7 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
         // but ensure that we don't search for the same
         // thing twice. This is called from multiple places
         // and needs to be smart about when it actually searches
-        var filter = currentFilter;
+        let filter = currentFilter;
         if (prevSearch === filter) return;
 
         prevSearch = filter;
@@ -265,7 +265,7 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
       }
 
       function scrollIntoView($element, snapTop) {
-        var el = $element[0];
+        let el = $element[0];
 
         if (!el) return;
 
diff --git a/src/ui/public/directives/truncated.js b/src/ui/public/directives/truncated.js
index 325d7955ef38..a46197a707a8 100644
--- a/src/ui/public/directives/truncated.js
+++ b/src/ui/public/directives/truncated.js
@@ -1,6 +1,6 @@
 import $ from 'jquery';
 import uiModules from 'ui/modules';
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('kbnTruncated', function ($compile) {
   return {
@@ -10,14 +10,14 @@ module.directive('kbnTruncated', function ($compile) {
       length: '@'
     },
     template: function ($element, attrs) {
-      var template = '<span>{{text}}</span>';
+      let template = '<span>{{text}}</span>';
       template += '<span ng-if="orig.length > length"> <a ng-click="toggle()">{{action}}</a></span>';
       return template;
     },
     link: function ($scope, $element, attrs) {
 
-      var fullText = $scope.orig;
-      var truncated = fullText.substring(0, $scope.length);
+      let fullText = $scope.orig;
+      let truncated = fullText.substring(0, $scope.length);
 
       if (fullText === truncated) {
         $scope.text = fullText;
diff --git a/src/ui/public/directives/validate_date_math.js b/src/ui/public/directives/validate_date_math.js
index bfb4e437d4fc..d9dad2aa5f30 100644
--- a/src/ui/public/directives/validate_date_math.js
+++ b/src/ui/public/directives/validate_date_math.js
@@ -19,7 +19,7 @@ uiModules.get('kibana').directive('validateDateMath', function () {
           return null;
         }
 
-        var moment = dateMath.parse(input);
+        let moment = dateMath.parse(input);
         ngModel.$setValidity('validDateMath', moment != null && moment.isValid());
         return input;
       }
diff --git a/src/ui/public/directives/validate_index_name.js b/src/ui/public/directives/validate_index_name.js
index fe41be26f5bd..1082616ee0e7 100644
--- a/src/ui/public/directives/validate_index_name.js
+++ b/src/ui/public/directives/validate_index_name.js
@@ -12,11 +12,11 @@ uiModules
         'ngModel': '='
       },
       link: function ($scope, elem, attr, ngModel) {
-        var illegalCharacters = ['\\', '/', '?', '"', '<', '>', '|', ' ', ','];
-        var isValid = function (input) {
+        let illegalCharacters = ['\\', '/', '?', '"', '<', '>', '|', ' ', ','];
+        let isValid = function (input) {
           if (input == null || input === '' || input === '.' || input === '..') return false;
 
-          var match = _.find(illegalCharacters, function (character) {
+          let match = _.find(illegalCharacters, function (character) {
             return input.indexOf(character) >= 0;
           });
           return !match;
@@ -24,7 +24,7 @@ uiModules
 
         // From User
         ngModel.$parsers.unshift(function (value) {
-          var valid = isValid(value);
+          let valid = isValid(value);
           ngModel.$setValidity('indexNameInput', valid);
           return valid ? value : undefined;
         });
diff --git a/src/ui/public/directives/validate_json.js b/src/ui/public/directives/validate_json.js
index 973aa7276433..bf4df84f69da 100644
--- a/src/ui/public/directives/validate_json.js
+++ b/src/ui/public/directives/validate_json.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import $ from 'jquery';
 import uiModules from 'ui/modules';
 
-var module = uiModules.get('kibana');
+let module = uiModules.get('kibana');
 
 module.directive('validateJson', function ($compile) {
   return {
diff --git a/src/ui/public/doc_table/components/table_header.js b/src/ui/public/doc_table/components/table_header.js
index 4fbdd83173bd..b0c0d56644d6 100644
--- a/src/ui/public/doc_table/components/table_header.js
+++ b/src/ui/public/doc_table/components/table_header.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import 'ui/filters/short_dots';
 import headerHtml from 'ui/doc_table/components/table_header.html';
 import uiModules from 'ui/modules';
-var module = uiModules.get('app/discover');
+let module = uiModules.get('app/discover');
 
 
 module.directive('kbnTableHeader', function (shortDotsFilter) {
@@ -16,9 +16,9 @@ module.directive('kbnTableHeader', function (shortDotsFilter) {
     template: headerHtml,
     controller: function ($scope) {
 
-      var sortableField = function (field) {
+      let sortableField = function (field) {
         if (!$scope.indexPattern) return;
-        var sortable = _.get($scope.indexPattern.fields.byName[field], 'sortable');
+        let sortable = _.get($scope.indexPattern.fields.byName[field], 'sortable');
         return sortable;
       };
 
@@ -34,22 +34,22 @@ module.directive('kbnTableHeader', function (shortDotsFilter) {
       $scope.headerClass = function (column) {
         if (!sortableField(column)) return;
 
-        var sorting = $scope.sorting;
-        var defaultClass = ['fa', 'fa-sort-up', 'table-header-sortchange'];
+        let sorting = $scope.sorting;
+        let defaultClass = ['fa', 'fa-sort-up', 'table-header-sortchange'];
 
         if (!sorting || column !== sorting[0]) return defaultClass;
         return ['fa', sorting[1] === 'asc' ? 'fa-sort-up' : 'fa-sort-down'];
       };
 
       $scope.moveLeft = function (column) {
-        var index = _.indexOf($scope.columns, column);
+        let index = _.indexOf($scope.columns, column);
         if (index === 0) return;
 
         _.move($scope.columns, index, --index);
       };
 
       $scope.moveRight = function (column) {
-        var index = _.indexOf($scope.columns, column);
+        let index = _.indexOf($scope.columns, column);
         if (index === $scope.columns.length - 1) return;
 
         _.move($scope.columns, index, ++index);
@@ -62,9 +62,9 @@ module.directive('kbnTableHeader', function (shortDotsFilter) {
       $scope.sort = function (column) {
         if (!column || !sortableField(column)) return;
 
-        var sorting = $scope.sorting = $scope.sorting || [];
+        let sorting = $scope.sorting = $scope.sorting || [];
 
-        var direction = sorting[1] || 'asc';
+        let direction = sorting[1] || 'asc';
         if (sorting[0] !== column) {
           direction = 'asc';
         } else {
diff --git a/src/ui/public/doc_table/components/table_row.js b/src/ui/public/doc_table/components/table_row.js
index 168e71a52ea7..7dfdfe24fa69 100644
--- a/src/ui/public/doc_table/components/table_row.js
+++ b/src/ui/public/doc_table/components/table_row.js
@@ -10,12 +10,12 @@ import noWhiteSpace from 'ui/utils/no_white_space';
 import openRowHtml from 'ui/doc_table/components/table_row/open.html';
 import detailsHtml from 'ui/doc_table/components/table_row/details.html';
 import uiModules from 'ui/modules';
-var module = uiModules.get('app/discover');
+let module = uiModules.get('app/discover');
 
 
 
 // guesstimate at the minimum number of chars wide cells in the table should be
-var MIN_LINE_LENGTH = 20;
+let MIN_LINE_LENGTH = 20;
 
 /**
  * kbnTableRow directive
@@ -26,8 +26,8 @@ var MIN_LINE_LENGTH = 20;
  * ```
  */
 module.directive('kbnTableRow', function ($compile) {
-  var cellTemplate = _.template(noWhiteSpace(require('ui/doc_table/components/table_row/cell.html')));
-  var truncateByHeightTemplate = _.template(noWhiteSpace(require('ui/partials/truncate_by_height.html')));
+  let cellTemplate = _.template(noWhiteSpace(require('ui/doc_table/components/table_row/cell.html')));
+  let truncateByHeightTemplate = _.template(noWhiteSpace(require('ui/partials/truncate_by_height.html')));
 
   return {
     restrict: 'A',
@@ -41,7 +41,7 @@ module.directive('kbnTableRow', function ($compile) {
       $el.after('<tr>');
       $el.empty();
 
-      var init = function () {
+      let init = function () {
         createSummaryRow($scope.row, $scope.row._id);
       };
 
@@ -53,7 +53,7 @@ module.directive('kbnTableRow', function ($compile) {
 
       // toggle display of the rows details, a full list of the fields from each row
       $scope.toggleRow = function () {
-        var $detailsTr = $el.next();
+        let $detailsTr = $el.next();
 
         $scope.open = !$scope.open;
 
@@ -90,10 +90,10 @@ module.directive('kbnTableRow', function ($compile) {
 
       // create a tr element that lists the value for each *column*
       function createSummaryRow(row) {
-        var indexPattern = $scope.indexPattern;
+        let indexPattern = $scope.indexPattern;
 
         // We just create a string here because its faster.
-        var newHtmls = [
+        let newHtmls = [
           openRowHtml
         ];
 
@@ -112,18 +112,18 @@ module.directive('kbnTableRow', function ($compile) {
           }));
         });
 
-        var $cells = $el.children();
+        let $cells = $el.children();
         newHtmls.forEach(function (html, i) {
-          var $cell = $cells.eq(i);
+          let $cell = $cells.eq(i);
           if ($cell.data('discover:html') === html) return;
 
-          var reuse = _.find($cells.slice(i + 1), function (cell) {
+          let reuse = _.find($cells.slice(i + 1), function (cell) {
             return $.data(cell, 'discover:html') === html;
           });
 
-          var $target = reuse ? $(reuse).detach() : $(html);
+          let $target = reuse ? $(reuse).detach() : $(html);
           $target.data('discover:html', html);
-          var $before = $cells.eq(i - 1);
+          let $before = $cells.eq(i - 1);
           if ($before.size()) {
             $before.after($target);
           } else {
@@ -151,8 +151,8 @@ module.directive('kbnTableRow', function ($compile) {
        * Fill an element with the value of a field
        */
       function _displayField(row, fieldName, breakWords) {
-        var indexPattern = $scope.indexPattern;
-        var text = indexPattern.formatField(row, fieldName);
+        let indexPattern = $scope.indexPattern;
+        let text = indexPattern.formatField(row, fieldName);
 
         if (breakWords) {
           text = addWordBreaks(text, MIN_LINE_LENGTH);
diff --git a/src/ui/public/doc_table/components/table_row/cell.html b/src/ui/public/doc_table/components/table_row/cell.html
index 55f1e17f0cde..ca28d024ff7a 100644
--- a/src/ui/public/doc_table/components/table_row/cell.html
+++ b/src/ui/public/doc_table/components/table_row/cell.html
@@ -1,5 +1,5 @@
 <%
-var attributes = '';
+let attributes = '';
 if (timefield) {
   attributes='class="discover-table-timefield" width="1%"';
 } else if (sourcefield) {
diff --git a/src/ui/public/doc_table/doc_table.js b/src/ui/public/doc_table/doc_table.js
index f9d0eec99fba..db3148a83152 100644
--- a/src/ui/public/doc_table/doc_table.js
+++ b/src/ui/public/doc_table/doc_table.js
@@ -25,15 +25,15 @@ uiModules.get('kibana')
       filter: '=?',
     },
     link: function ($scope) {
-      var notify = new Notifier();
+      let notify = new Notifier();
       $scope.limit = 50;
       $scope.persist = {
         sorting: $scope.sorting,
         columns: $scope.columns
       };
 
-      var prereq = (function () {
-        var fns = [];
+      let prereq = (function () {
+        let fns = [];
 
         return function register(fn) {
           fns.push(fn);
@@ -59,7 +59,7 @@ uiModules.get('kibana')
       $scope.$watch('columns', function (columns) {
         if (columns.length !== 0) return;
 
-        var $state = getAppState();
+        let $state = getAppState();
         $scope.columns.push('_source');
         if ($state) $state.replace();
       });
diff --git a/src/ui/public/doc_table/lib/get_sort.js b/src/ui/public/doc_table/lib/get_sort.js
index a92572a6eae3..e9f99615b1fc 100644
--- a/src/ui/public/doc_table/lib/get_sort.js
+++ b/src/ui/public/doc_table/lib/get_sort.js
@@ -7,7 +7,7 @@ import _ from 'lodash';
  * @returns {object} a sort object suitable for returning to elasticsearch
  */
 function getSort(sort, indexPattern) {
-  var sortObj = {};
+  let sortObj = {};
   let field;
   let direction;
 
diff --git a/src/ui/public/doc_title/doc_title.js b/src/ui/public/doc_title/doc_title.js
index 5cff0b94fe56..5bd02d6af0f3 100644
--- a/src/ui/public/doc_title/doc_title.js
+++ b/src/ui/public/doc_title/doc_title.js
@@ -11,16 +11,16 @@ uiModules.get('kibana')
   $rootScope.$watch(_.bindKey(chrome, 'getActiveTabTitle'), docTitle.update);
 })
 .service('docTitle', function ($rootScope) {
-  var baseTitle = document.title;
-  var self = this;
+  let baseTitle = document.title;
+  let self = this;
 
   let lastChange;
 
   function render() {
     lastChange = lastChange || [];
 
-    var parts = [lastChange[0]];
-    var activeTabTitle = chrome.getActiveTabTitle();
+    let parts = [lastChange[0]];
+    let activeTabTitle = chrome.getActiveTabTitle();
 
     if (activeTabTitle) parts.push(activeTabTitle);