src/datahandler/default.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 default implementation used for simple line charts.
   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
  17 /**
  18  * @constructor
  19  * @extends Dygraph.DataHandler
  20  */
  21 var DefaultHandler = function() {
  22 };
  23
  24 DefaultHandler.prototype = new DygraphDataHandler();
  25
  26 /** @inheritDoc */
  27 DefaultHandler.prototype.extractSeries = function(rawData, i, options) {
  28   // TODO(danvk): pre-allocate series here.
  29   var series = [];
  30   var logScale = options.get('logscale');
  31   for ( var j = 0; j < rawData.length; j++) {
  32     var x = rawData[j][0];
  33     var point = rawData[j][i];
  34     if (logScale) {
  35       // On the log scale, points less than zero do not exist.
  36       // This will create a gap in the chart.
  37       if (point <= 0) {
  38         point = null;
  39       }
  40     }
  41     series.push([ x, point ]);
  42   }
  43   return series;
  44 };
  45
  46 /** @inheritDoc */
  47 DefaultHandler.prototype.rollingAverage = function(originalData, rollPeriod,
  48     options) {
  49   rollPeriod = Math.min(rollPeriod, originalData.length);
  50   var rollingData = [];
  51
  52   var i, j, y, sum, num_ok;
  53   // Calculate the rolling average for the first rollPeriod - 1 points
  54   // where
  55   // there is not enough data to roll over the full number of points
  56   if (rollPeriod == 1) {
  57     return originalData;
  58   }
  59   for (i = 0; i < originalData.length; i++) {
  60     sum = 0;
  61     num_ok = 0;
  62     for (j = Math.max(0, i - rollPeriod + 1); j < i + 1; j++) {
  63       y = originalData[j][1];
  64       if (y === null || isNaN(y))
  65         continue;
  66       num_ok++;
  67       sum += originalData[j][1];
  68     }
  69     if (num_ok) {
  70       rollingData[i] = [ originalData[i][0], sum / num_ok ];
  71     } else {
  72       rollingData[i] = [ originalData[i][0], null ];
  73     }
  74   }
  75
  76   return rollingData;
  77 };
  78
  79 /** @inheritDoc */
  80 DefaultHandler.prototype.getExtremeYValues = function(series, dateWindow,
  81     options) {
  82   var minY = null, maxY = null, y;
  83   var firstIdx = 0, lastIdx = series.length - 1;
  84
  85   for ( var j = firstIdx; j <= lastIdx; j++) {
  86     y = series[j][1];
  87     if (y === null || isNaN(y))
  88       continue;
  89     if (maxY === null || y > maxY) {
  90       maxY = y;
  91     }
  92     if (minY === null || y < minY) {
  93       minY = y;
  94     }
  95   }
  96   return [ minY, maxY ];
  97 };
  98
  99 export default DefaultHandler;