Sorting an array of objects in Chrome

The ECMAScript standard does not guarantee Array.sort is a stable sort. Chrome (the V8 engine) uses in-place QuickSort internally (for arrays of size ≥ 22, else insertion sort) which is fast but not stable.

To fix it, make customSort compare with .b as well, eliminating the need of stability of the sorting algorithm.

The V8 sort is not stable, unfortunately. I'll see if I can dig up the Chromium bug about this.

V8 sort is now stable!

May be you know it already but you can use an array to sort on multiple columns and avoid this bug:

var customSort = function(a,b) {
    return [a.a, a.b] > [b.a, b.b] ? 1:-1;
}