手写实现 apply

[lovelmh13]

手写实现 apply

并不是直接用 call 实现

Function.prototype.myApply = function (that, args) {
  if (typeof that === 'undefined' || typeof that === null) {
    that = window
  }
  if (typeof args === 'undefined' || typeof args === null) {
    args = []
  }
  
  that = new Object(that) // 看不懂，感觉没有也无所谓

  const thatKey = 'thatKey'
  that[thatKey] = this
  const res = that[thatKey](...args)
  delete that[thatKey]
  
  return res
}