[removed] Sort array and return an array of indicies that indicates the position of the sorted elements with respect to the original elements

Question

Suppose I have a Javascript array, like so:

var test = [\'b\', \'c\', \'d\', \'a\'];

I want to sort the array. Obviously, I can just do th

Answer 1

Array.prototype.sortIndices = function (func) {
    var i = j = this.length,
        that = this;

    while (i--) {
        this[i] = { k: i, v: this[i] };
    }

    this.sort(function (a, b) {
        return func ? func.call(that, a.v, b.v) : 
                      a.v < b.v ? -1 : a.v > b.v ? 1 : 0;
    });

    while (j--) {
        this[j] = this[j].k;
    }
}

YMMV on how you feel about adding functions to the Array prototype and mutating arrays inline, but this allows sorting of an array of any objects that can be compared. It takes an optional function that can be used for sorting, much like Array.prototype.sort.

An example,

var test = [{b:2},{b:3},{b:4},{b:1}];

test.sortIndices(function(a,b) { return a.b - b.b; });

console.log(test); // returns [3,0,1,2]