array permutations

array_permutate.js

function array_permutate(set /*, additionalSets*/ ) {
  var additionalSets = Array.prototype.slice.call(arguments, 1);
  if (additionalSets.length === 0) {
    return set.map(function (item) { return [item]; });
  }
  var permutations = array_permutate.apply(null, additionalSets);
  var result = [];
  for (var i = 0; i < set.length; i++) {
    for (var j = 0; j < permutations.length; j++) {
      result.push([set[i]].concat(permutations[j]));
    }
  }
  return result;
}

console.log(array_permutate(
  [1, 2, 3], 
  ['a', 'b', 'c'], 
  ['A', 'B', 'C']
));