// merge 1-2 arrays
module.exports = function concat2(set1, set2) {
  set1 = set1 || []
  set2 = set2 || []
  var idx
  var len1 = set1.length
  var len2 = set2.length
  var result = []

  idx = 0
  while (idx < len1) {
    result[result.length] = set1[idx]
    idx += 1
  }
  idx = 0
  while (idx < len2) {
    result[result.length] = set2[idx]
    idx += 1
  }
  return result
}