code: function each(els, fn) {
    for (var i = 0, len = (els || []).length, el; i < len; i++) {
      el = els[i]
      // return false -> remove current item during loop
      if (el != null && fn(el, i) === false) i--
    }
    return els
  }
docs: Loops an array
  @param   { Array } els - collection of items
  @param   {Function} fn - callback function
  @returns { Array } the array looped