SO - 24277656

by Arun P Johny

JavaScript

var array = [{
    value: 20,
    color: 'F88C00'
}, {
    value: 40,
    color: 'D8605F'
}, {
    value: 20,
    color: '72C380'
}, {
    value: 20,
    color: '2C7282'
}, {
    value: 20,
    color: '72C380'
}];

var op = [],
    map = {}, it, item;
for (var i = 0; i < array.length; i++) {
    it = array[i];
    item = map[it.color];
    if (item) {
        item.value += it.value;
    } else {
        map[it.color] = item = {
            value: it.value,
            color: it.color
        };
        op.push(item);
    }
}
console.log(JSON.stringify(op))