Array of object inside array of grouped objects with calculated total in JavaScript

Question

as the title said, I need to push array of objects inside grouped objects. I found example here and it goes:

function groupBy(array, col, value) {
    var r = [], o = {};
    array.forEach(function (a) {
        if (!o[a[col]]) {
            o[a[col]] = {};
            o[a[col]][col] = a[col];
            o[a[col]][value] = 0;
            r.push(o[a[col]]);

        }
        o[a[col]][value] += +a[value];
    });
    return r;
};

var data = [{ Phase: "Phase 1", Step: "Step 1", Task: "Task 1", Value: "5" }, { Phase: "Phase 1", Step: "Step 1", Task: "Task 2", Value: "10" }, { Phase: "Phase 1", Step: "Step 2", Task: "Task 1", Value: "15" }, { Phase: "Phase 1", Step: "Step 2", Task: "Task 2", Value: "20" }, { Phase: "Phase 2", Step: "Step 1", Task: "Task 1", Value: "25" }, { Phase: "Phase 2", Step: "Step 1", Task: "Task 2", Value: "30" }, { Phase: "Phase 2", Step: "Step 2", Task: "Task 1", Value: "35" }, { Phase: "Phase 2", Step: "Step 2", Task: "Task 2", Value: "40" }];

document.write('<pre>' + JSON.stringify(groupBy(data, 'Phase', 'Value'), 0, 4) + '</pre>');

my result is:

[
    {
        "Phase": "Phase 1",
        "Value": 50
    },
    {
        "Phase": "Phase 2",
        "Value": 130
    }
]

What I want to get is that inside my grouped object is array of objects with properties: Task and Value (for each task I want value).

I tried this:

function groupBy(array, col, col2, value) {
    var r = [], o = {};
    array.forEach(function (a) {
        if (!o[a[col]]) {
            o[a[col]] = {};
            o[a[col]][col] = a[col];
            o[a[col]][col2] = a[col2];
            o[a[col]][value] = 0;
            r.push(o[a[col]]);

        }
        o[a[col]][value] += +a[value];
    });
    return r;
};

and add "Task" parameter but only I got was:

[
    {
        "Phase": "Phase 1",
        "Task" : "Task 1",
        "Value": 50
    },
    {
        "Phase": "Phase 2",
        "Task" : "Task 1",
        "Value": 130
    }
]

Thanks for help!

Haizhou Liu · Accepted Answer · 2016-06-13 20:03:34Z

1

You are using Phase and Task for the key in hash table. So the code need to be changed like this

function groupBy(array, col, col2, value) {
  var r = [],
    o = {};
  array.forEach(function(a) {
    // key is not 'Phase' only, it should combine 'Phase' and 'Task', others are the same.
    if (!o[a[col] + a[col2]]) {
      o[a[col] + a[col2]] = {};
      o[a[col] + a[col2]][col] = a[col];
      o[a[col] + a[col2]][col2] = a[col2];
      o[a[col] + a[col2]][value] = 0;
      r.push(o[a[col] + a[col2]]);

    }
    o[a[col] + a[col2]][value] += +a[value];
  });
  return r;
};

Check out here.

answered Jun 13, 2016 at 20:03

Haizhou Liu

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