find sets of positive integers which sum to another integer

sums.js

var sums = function(num) {
  var sets = [[num]];
  for (var i = 1; i <= num/2; i++) {
    var left = sums(i);
    var right = sums(num-i);
    left.forEach(function(lhs) {
      right.forEach(function(rhs) {
        sets.push(lhs.concat(rhs).sort());
      })
    })
  }
  return uniq(sets);
}

function uniq(list) {
  var cache = {};
  for (var i in list) { cache[list[i].toString()] = list[i]; }
  var result = [];
  for (var p in cache) { result.push(cache[p]); }
  return result;
}