Merge two dates series into one

Question

I need to do some chart in Dygraph.js, with multiple series.

For example i have this dataset:

array1 = [ ['2016-03-16', 10,]
           ['2016-03-17', 20,]
           ['2016-03-19', 20,]
           ['2016-03-20', 15,]
         ];

array2 = [ ['2016-03-16', 30,]
           ['2016-03-18', 50,]
           ['2016-03-20', 30,]
         ];

And i want to merge this arrays into one:

merged = [ ['2016-03-16', 10, 30]
           ['2016-03-17', 20, null]
           ['2016-03-18', null, 50]
           ['2016-03-19', 20, null]
           ['2016-03-20', 15, 30,]
         ];

Ofcorse dates are in more complex format: YYYY-MM-DD HH:mm:ss. I'm using moment.js for dates operation.

How to merge these arrays in the fastest way?

Answer 1

A solution for any count of series.

var array1 = [['2016-03-16', 10], ['2016-03-17', 20], ['2016-03-19', 20], ['2016-03-20', 15]],
    array2 = [['2016-03-16', 30], ['2016-03-18', 50], ['2016-03-20', 30]],
    merged = function (array) {
        var o = {}, r = [];
        array.forEach(function (a, i) {
            a.forEach(function (b) {
                if (!o[b[0]]) {
                    o[b[0]] = Array.apply(null, { length: array.length + 1}).map(function () { return null; });
                    o[b[0]][0] = b[0];
                    r.push(o[b[0]]);
                }
                o[b[0]][i + 1] = b[1];
            });
        });
        return r.sort(function (a, b) { return a[0].localeCompare(b[0]); });
    }([array1, array2]);

document.write('<pre>' + JSON.stringify(merged, 0, 4) + '</pre>');