Sets and combinations

sets.js

function findSetsIn(list, noEmptySet) {
    var result = noEmptySet ? [] : [[]];
    for (var i = 0; i < list.length; i++) {
        var base = [ list[i] ];
        result.push(base);
        var tail = findSetsIn(list.slice(i + 1), true);
        for (var j = 0; j < tail.length; j++) {
            result.push(base.concat(tail[j]));
        }
    }
    return result;
}

findSetsIn([1, 2, 3, 4, 5])