Set headers

.gitignore

@@ -1,2 +1,3 @@
 node_modules/
+.idea/
 example/output.xlsx

lib/json2xls.js

@@ -1,9 +1,14 @@
 var nodeExcel = require('excel-export');
 
+/**
+ *
+ * @param {array|object} json
+ * @param {array|object} config
+ * @returns {*}
+ */
 var transform = function(json,config) {
     var conf = transform.prepareJson(json,config);
-    var result = nodeExcel.execute(conf);
-    return result;
+    return nodeExcel.execute(conf);
 };
 
 //get a xls type based on js type
@@ -31,7 +36,7 @@ function getByString(object, path) {
     while (a.length) {
         var n = a.shift();
         if (n in object) {
-            object = (object[n]==undefined)?null:object[n];
+            object = (object[n] === undefined) ? null : object[n];
         } else {
             return null;
         }
@@ -42,55 +47,59 @@ function getByString(object, path) {
 
 //prepare json to be in the correct format for excel-export
 transform.prepareJson = function(json,config) {
-    var res = {};
-    var conf = config||{};
-    var jsonArr = [].concat(json);
-    var fields = conf.fields || Object.keys(jsonArr[0]||{});
-    var types = [];
-    if (!(fields instanceof Array)) {
-        types = Object.keys(fields).map(function(key) {
-            return fields[key];
-        });
-        fields = Object.keys(fields);
-    }
-    //cols
-    res.cols = fields.map(function(key,i) {
-        return {
-            caption: key,
-            type: getType(jsonArr[0][key],types[i]),
-            beforeCellWrite: function(row, cellData, eOpt){
-                eOpt.cellType = getType(cellData,types[i]);
-                return cellData;
-            }
-        };
+  var res = {};
+  var conf = config||{};
+  var jsonArr = [].concat(json);
+  var fields = conf.fields || Object.keys(jsonArr[0]||{});
+  var types = [];
+  var headers = [];
+  if (!(fields instanceof Array)) {
+    types = Object.keys(fields).map(function(key) {
+      return fields[key]['type'] !== undefined ? fields[key]['type'] : fields[key];
     });
-    //rows
-    res.rows = jsonArr.map(function(row) {
-        return fields.map(function(key) {
-            var value = getByString(row,key);
-            //stringify objects
-            if(value && value.constructor == Object) value = JSON.stringify(value);
-            //replace illegal xml characters with a square
-            //see http://www.w3.org/TR/xml/#charsets
-            //#x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]
-            if (typeof value === 'string') {
-                value = value.replace(/[^\u0009\u000A\u000D\u0020-\uD7FF\uE000-\uFFFD\u10000-\u10FFFF]/g,'');
-            }
-            return value;
-        });
+    headers = Object.keys(fields).map(function(key) {
+      return fields[key]['header'] !== undefined ? fields[key]['header'] : key;
     });
-    //add style xml if given
-    if (conf.style) {
-        res.stylesXmlFile = conf.style;
-    }
-    return res;
+    fields = Object.keys(fields);
+  }
+  //cols
+  res.cols = fields.map(function(key,i) {
+    return {
+      caption: headers[i],
+      type: getType(jsonArr[0][key],types[i]),
+      beforeCellWrite: function(row, cellData, eOpt){
+        eOpt.cellType = getType(cellData,types[i]);
+        return cellData;
+      }
+    };
+  });
+  //rows
+  res.rows = jsonArr.map(function(row) {
+    return fields.map(function(key) {
+      var value = getByString(row,key);
+      //stringify objects
+      if(value && value.constructor == Object) value = JSON.stringify(value);
+      //replace illegal xml characters with a square
+      //see http://www.w3.org/TR/xml/#charsets
+      //#x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]
+      if (typeof value === 'string') {
+        value = value.replace(/[^\u0009\u000A\u000D\u0020-\uD7FF\uE000-\uFFFD\u10000-\u10FFFF]/g,'');
+      }
+      return value;
+    });
+  });
+  //add style xml if given
+  if (conf.style) {
+    res.stylesXmlFile = conf.style;
+  }
+  return res;
 };
 
-transform.middleware = function(req,res,next) {
-    res.xls = function(fn,data,config) {
-        var xls = transform(data,config);
+transform.middleware = function(req, res, next) {
+    res.xls = function(fn, data, config) {
+        var xls = transform(data, config);
         res.setHeader('Content-Type', 'application/vnd.openxmlformats');
-        res.setHeader("Content-Disposition", "attachment; filename=" + fn);
+        res.setHeader('Content-Disposition', 'attachment; filename=' + fn);
         res.end(xls, 'binary');
     };
     next();

readme.md

@@ -62,6 +62,7 @@ The following options are supported:
     - fields: either an array or map containing field configuration:
         - array: a list of names of fields to be exported, in that order
         - object: a map of names of fields to be exported and the types of those fields. Supported types are 'number','string','bool'
+        - object: {'poo':{header:'Some Header for poo', type:'number'}}
 
 Example:
 
@@ -83,4 +84,24 @@ Example:
         fields: {poo:'string'}
     });
 
+    fs.writeFileSync('data.xlsx', xls, 'binary');
+Example with headers:
+
+    var json2xls = require('json2xls');
+    var json = {
+        foo: 'bar',
+        qux: 'moo',
+        poo: 123,
+        stux: new Date()
+    }
+
+    //export only the field 'poo'
+    var xls = json2xls(json,{
+        fields: {
+            'poo':{header:'Some Header for poo', type:'number'},
+            'qux':{header:'Some Header for qux', type:'string'}
+        }
+    });
+
+
     fs.writeFileSync('data.xlsx', xls, 'binary');