Array.prototype.unshift

[Sunny]

Array.prototype.myUnshift = function (...items) {
    this.reverse().push(...items.reverse())
    this.reverse()
    return this.length
}

[kangkang123269]

Array.prototype.unshift = function() {
  var itemsToAdd = arguments.length;
  var len = this.length;
  for (var i = len - 1; i >= 0; i--) {
    this[i + itemsToAdd] = this[i];
  }
  for (var j = 0; j < itemsToAdd; j++) {
    this[j] = arguments[j];
  }
  return this.length;
};