Use count for consistency.

src/threshold/freedmanDiaconis.js

@@ -1,9 +1,6 @@
-import {map} from "../array.js";
-import ascending from "../ascending.js";
-import number from "../number.js";
+import count from "../count.js";
 import quantile from "../quantile.js";
 
 export default function(values, min, max) {
-  values = map.call(values, number).sort(ascending);
-  return Math.ceil((max - min) / (2 * (quantile(values, 0.75) - quantile(values, 0.25)) * Math.pow(values.length, -1 / 3)));
+  return Math.ceil((max - min) / (2 * (quantile(values, 0.75) - quantile(values, 0.25)) * Math.pow(count(values), -1 / 3)));
 }

src/threshold/scott.js

@@ -1,5 +1,6 @@
+import count from "../count.js";
 import deviation from "../deviation.js";
 
 export default function(values, min, max) {
-  return Math.ceil((max - min) / (3.5 * deviation(values) * Math.pow(values.length, -1 / 3)));
+  return Math.ceil((max - min) / (3.5 * deviation(values) * Math.pow(count(values), -1 / 3)));
 }

src/threshold/sturges.js

@@ -1,3 +1,5 @@
+import count from "../count.js";
+
 export default function(values) {
-  return Math.ceil(Math.log(values.length) / Math.LN2) + 1;
+  return Math.ceil(Math.log(count(values)) / Math.LN2) + 1;
 }

test/threshold/freedmanDiaconic-test.js

@@ -0,0 +1,7 @@
+var tape = require("tape"),
+    arrays = require("../../");
+
+tape("thresholdFreedmanDiaconis(values, min, max) returns the expected result", function(test) {
+  test.equal(arrays.thresholdFreedmanDiaconis([4, 3, 2, 1, NaN], 1, 4), 2);
+  test.end();
+});

test/threshold/scott-test.js

@@ -0,0 +1,7 @@
+var tape = require("tape"),
+    arrays = require("../../");
+
+tape("thresholdScott(values, min, max) returns the expected result", function(test) {
+  test.equal(arrays.thresholdScott([4, 3, 2, 1, NaN], 1, 4), 2);
+  test.end();
+});

test/threshold/sturges-test.js

@@ -0,0 +1,7 @@
+var tape = require("tape"),
+    arrays = require("../../");
+
+tape("thresholdSturges(values, min, max) returns the expected result", function(test) {
+  test.equal(arrays.thresholdSturges([4, 3, 2, 1, NaN], 1, 4), 3);
+  test.end();
+});