Util.js

   1 /**
   2  * @fileoverview Utility functions for Dygraphs.
   3  *
   4  * @author konigsberg@google.com (Robert Konigsberg)
   5  */
   6
   7 import * as utils from '../../src/dygraph-utils';
   8
   9 var Util = {};
  10
  11 /**
  12  * Get the y-labels for a given axis.
  13  *
  14  * You can specify a parent if more than one graph is in the document.
  15  */
  16 Util.getYLabels = function(axis_num, parent) {
  17   axis_num = axis_num || "";
  18   parent = parent || document;
  19   var y_labels = parent.getElementsByClassName("dygraph-axis-label-y" + axis_num);
  20   var ary = [];
  21   for (var i = 0; i < y_labels.length; i++) {
  22     ary.push(y_labels[i].innerHTML.replace(/&#160;|&nbsp;/g, ' '));
  23   }
  24   return ary;
  25 };
  26
  27 /**
  28  * Get the x-labels for a given axis.
  29  *
  30  * You can specify a parent if more than one graph is in the document.
  31  */
  32 Util.getXLabels = function(parent) {
  33   parent = parent || document;
  34   var x_labels = parent.getElementsByClassName("dygraph-axis-label-x");
  35   var ary = [];
  36   for (var i = 0; i < x_labels.length; i++) {
  37     ary.push(x_labels[i].innerHTML.replace(/&#160;|&nbsp;/g, ' '));
  38   }
  39   return ary;
  40 };
  41
  42 /**
  43  * Returns all text in tags w/ a given css class, sorted.
  44  * You can specify a parent if more than one graph is on the document.
  45  */
  46 Util.getClassTexts = function(css_class, parent) {
  47   parent = parent || document;
  48   var texts = [];
  49   var els = parent.getElementsByClassName(css_class);
  50   for (var i = 0; i < els.length; i++) {
  51     texts[i] = els[i].textContent;
  52   }
  53   texts.sort();
  54   return texts;
  55 };
  56
  57 // Convert &nbsp; to a normal space
  58 Util.nbspToSpace = function(str) {
  59   var re = new RegExp(String.fromCharCode(160), 'g');
  60   return str.replace(re, ' ');
  61 };
  62
  63 Util.getLegend = function(parent) {
  64   parent = parent || document;
  65   var legend = parent.getElementsByClassName("dygraph-legend")[0];
  66   return Util.nbspToSpace(legend.textContent);
  67 };
  68
  69 /**
  70  * Assert that all elements have a certain style property.
  71  */
  72 Util.assertStyleOfChildren = function(selector, property, expectedValue) {
  73   assert.isTrue(selector.length > 0);
  74   for (var idx = 0; idx < selector.length; idx++) {
  75     var child = selector[idx];
  76     assert.equal(expectedValue, window.getComputedStyle(child)[property]);
  77   }
  78 };
  79
  80
  81 /**
  82  * Takes in an array of strings and returns an array of floats.
  83  */
  84 Util.makeNumbers = function(ary) {
  85   var ret = [];
  86   for (var i = 0; i < ary.length; i++) {
  87     ret.push(parseFloat(ary[i]));
  88   }
  89   return ret;
  90 };
  91
  92
  93 /**
  94  * Sample a pixel from the canvas.
  95  * Returns an [r, g, b, a] tuple where each values is in [0, 255].
  96  * This is _very_ slow! If you want to sample many pixels, use PixelSampler.
  97  */
  98 Util.samplePixel = function(canvas, x, y) {
  99   var ctx = canvas.getContext("2d");  // bypasses Proxy if applied.
 100
 101   var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
 102
 103   var scale = utils.getContextPixelRatio(ctx);
 104
 105   var i = 4 * (x * scale + imageData.width * y * scale);
 106   var d = imageData.data;
 107   return [d[i], d[i+1], d[i+2], d[i+3]];
 108 };
 109
 110 /**
 111  * Overrides the browser's built-in XMLHttpRequest with a mock.
 112  * Usage:
 113  *
 114  * var mockXhr = Util.overrideXMLHttpRequest(your_data);
 115  * ... call code that does an XHR ...
 116  * mockXhr.respond();  // restores default behavior.
 117  * ... do your assertions ...
 118  */
 119 Util.overrideXMLHttpRequest = function(data) {
 120   var originalXMLHttpRequest = XMLHttpRequest;
 121
 122   var requests = [];
 123   var FakeXMLHttpRequest = function () {
 124     requests.push(this);
 125   };
 126   FakeXMLHttpRequest.prototype.open = function () {};
 127   FakeXMLHttpRequest.prototype.send = function () {
 128     this.readyState = 4;
 129     this.status = 200;
 130     this.responseText = data;
 131   };
 132   FakeXMLHttpRequest.restore = function() {
 133     window.XMLHttpRequest = originalXMLHttpRequest;
 134   };
 135   FakeXMLHttpRequest.respond = function() {
 136     for (var i = 0; i < requests.length; i++) {
 137       requests[i].onreadystatechange();
 138     }
 139     FakeXMLHttpRequest.restore();
 140   };
 141   window.XMLHttpRequest = FakeXMLHttpRequest;
 142   return FakeXMLHttpRequest;
 143 };
 144
 145 /**
 146  * Format a date as 2000/01/23
 147  * @param {number} dateMillis Millis since epoch.
 148  * @return {string} The date formatted as YYYY-MM-DD.
 149  */
 150 Util.formatDate = function(dateMillis) {
 151   return utils.dateString_(dateMillis).slice(0, 10);  // 10 == "YYYY/MM/DD".length
 152 };
 153
 154 /**
 155  * Capture console.{log,warn,error} statements into obj.
 156  * obj will look like {log:[], warn:[], error:[]}
 157  * This returns a function which will restore the original console.
 158  */
 159 Util.captureConsole = function(obj) {
 160   obj.log = [];
 161   obj.warn = [];
 162   obj.error = [];
 163   var orig = [console.log, console.warn, console.error];
 164   console.log = function(text) { obj.log.push(text); };
 165   console.warn = function(text) { obj.warn.push(text); };
 166   console.error = function(text) { obj.error.push(text); };
 167
 168   return function() {
 169     console.log = orig[0];
 170     console.warn = orig[1];
 171     console.error = orig[2];
 172   };
 173 };
 174
 175 export default Util;