binary sets

bin-sets.js

function setsOf(list) {
    var l = list.length;
    var sets = [];
    var total = 1 << l;
    for (var i = 0; i < total; i++) {
        var sub = [];
        for (var j = 0; j < l; j++) {
            if (i & (1 << j)) {
                sub.push(list[j]);
            }
        }
        sets.push(sub);
    }
    return sets;
}

setsOf([1,2,3,4])