src/datahandler/default-fractions.js

   1 /**
   2  * @license
   3  * Copyright 2013 David Eberlein (david.eberlein@ch.sauter-bc.com)
   4  * MIT-licensed (http://opensource.org/licenses/MIT)
   5  */
   6
   7 /**
   8  * @fileoverview DataHandler implementation for the fractions option.
   9  * @author David Eberlein (david.eberlein@ch.sauter-bc.com)
  10  */
  11
  12 /*global Dygraph:false */
  13 "use strict";
  14
  15 import DygraphDataHandler from './datahandler';
  16 import DefaultHandler from './default';
  17
  18 /**
  19  * @extends DefaultHandler
  20  * @constructor
  21  */
  22 var DefaultFractionHandler = function() {
  23 };
  24
  25 DefaultFractionHandler.prototype = new DefaultHandler();
  26
  27 DefaultFractionHandler.prototype.extractSeries = function(rawData, i, options) {
  28   // TODO(danvk): pre-allocate series here.
  29   var series = [];
  30   var x, y, point, num, den, value;
  31   var mult = 100.0;
  32   var logScale = options.get('logscale');
  33   for ( var j = 0; j < rawData.length; j++) {
  34     x = rawData[j][0];
  35     point = rawData[j][i];
  36     if (logScale && point !== null) {
  37       // On the log scale, points less than zero do not exist.
  38       // This will create a gap in the chart.
  39       if (point[0] <= 0 || point[1] <= 0) {
  40         point = null;
  41       }
  42     }
  43     // Extract to the unified data format.
  44     if (point !== null) {
  45       num = point[0];
  46       den = point[1];
  47       if (num !== null && !isNaN(num)) {
  48         value = den ? num / den : 0.0;
  49         y = mult * value;
  50         // preserve original values in extras for further filtering
  51         series.push([ x, y, [ num, den ] ]);
  52       } else {
  53         series.push([ x, num, [ num, den ] ]);
  54       }
  55     } else {
  56       series.push([ x, null, [ null, null ] ]);
  57     }
  58   }
  59   return series;
  60 };
  61
  62 DefaultFractionHandler.prototype.rollingAverage = function(originalData, rollPeriod,
  63     options) {
  64   rollPeriod = Math.min(rollPeriod, originalData.length);
  65   var rollingData = [];
  66
  67   var i;
  68   var num = 0;
  69   var den = 0; // numerator/denominator
  70   var mult = 100.0;
  71   for (i = 0; i < originalData.length; i++) {
  72     num += originalData[i][2][0];
  73     den += originalData[i][2][1];
  74     if (i - rollPeriod >= 0) {
  75       num -= originalData[i - rollPeriod][2][0];
  76       den -= originalData[i - rollPeriod][2][1];
  77     }
  78
  79     var date = originalData[i][0];
  80     var value = den ? num / den : 0.0;
  81     rollingData[i] = [ date, mult * value ];
  82   }
  83
  84   return rollingData;
  85 };
  86
  87 export default DefaultFractionHandler;