javascript - How to format my json data for stack column chart in HighCharts

Question

Here is my json data

var data = [
    {"unit":"a", "status":"Stopped / Idle", "val":21.2022222222222222},
    {"unit":"a", "status":"Working", "val":53.3066666666666667},
    {"unit":"a", "status":"Headland Turning", "val":0.04694444444444444444},
    {"unit":"a", "status":"Transport", "val":5.1425000000000000},
    {"unit":"b", "status":"Stopped / Idle", "val":334.7358333333333333},
    {"unit":"b", "status":"Working", "val":212.6386111111111111},
    {"unit":"b", "status":"Headland Turning", "val":26.2955555555555556},
    {"unit":"b", "status":"Transport", "val":0.00444444444444444444}
];

unit is the category

I want the data could be formatted in the following way so that I can plug in to series option in HighCharts:

series: [{
                name: 'Stopped / Idle',
                data: [21.2022222222222222, 334.7358333333333333]},
            {
                name: 'Working',
                data: [53.3066666666666667, 212.6386111111111111]},
            {
                name: 'Headland Turning',
                data: [0.04694444444444444444, 26.2955555555555556]},
            {
                name: 'Transport',
                data: [5.1425000000000000, 0.00444444444444444444]}]
        });

Thank you.

Answer 1

var data = [
    {"unit":"a", "status":"Stopped / Idle", "val":21.2022222222222222},
    {"unit":"a", "status":"Working", "val":53.3066666666666667},
    {"unit":"a", "status":"Headland Turning", "val":0.04694444444444444444},
    {"unit":"a", "status":"Transport", "val":5.1425000000000000},
    {"unit":"b", "status":"Stopped / Idle", "val":334.7358333333333333},
    {"unit":"b", "status":"Working", "val":212.6386111111111111},
    {"unit":"b", "status":"Headland Turning", "val":26.2955555555555556},
    {"unit":"b", "status":"Transport", "val":0.00444444444444444444}
];
var seriesData = [];
var xCategories = [];
var i, cat;
for(i = 0; i < data.length; i++){
     cat = 'Unit ' + data[i].unit;
     if(xCategories.indexOf(cat) === -1){
        xCategories[xCategories.length] = cat;
     }
}
for(i = 0; i < data.length; i++){
    if(seriesData){
      var currSeries = seriesData.filter(function(seriesObject){ return seriesObject.name == data[i].status;});
      if(currSeries.length === 0){
          currSeries = seriesData[seriesData.length] = {name: data[i].status, data: []};
      } else {
          currSeries = currSeries[0];
      }
      var index = currSeries.data.length;
      currSeries.data[index] = data[i].val;
    } else {
       seriesData[0] = {name: data[i].status, data: [data[i].val]}
    }
}

Now that you've seriesData and xCategories you can instantiate the chart by using something similar to

  chart = new Highchart({chart: {renderTo: 'chart-div', 
                                   type: 'column'
                                  }, 
                           plotOptions: {column: {stacking: 'normal'}},
                           xAxis:{ categories: xCategories}, 
                           series: seriesData
                         });

EDIT: Here's the jsFiddle: http://jsfiddle.net/sujay/UMeGS/