Sort an array of objects based on another array of ids

Question

I have 2 arrays

a = [2,3,1,4]
b = [{id: 1}, {id: 2}, {id: 3}, {id: 4}]

How do I get b sorted based on a? My desir

Answer 1

This solution uses Array#sort with a helper object c for the indices.

{
    "1": 2,
    "2": 0,
    "3": 1,
    "4": 3
}

var a = [2, 3, 1, 4],
    b = [{ id: 1 }, { id: 2 }, { id: 3 }, { id: 4 }],
    c = a.reduce(function (r, a, i) {
        r[a] = i;
        return r;
    }, {});

b.sort(function (x, y) {
    return c[x.id] - c[y.id];
});

document.write('
' + JSON.stringify(b, 0, 4) + '
');

For greater objects, I suggest to use Sorting with map.