function newPolyfill () {
        //创建新对象
  let newObject = null,flag
        //拿到构造函数
  const constructor = Array.prototype.shift.call(arguments)
  if(typeof constructor !== 'function') {
    console.err('error')
    return
  }
        //把对象的原型设置为函数的prototype对象
  newObject = Object.create(constructor.prototype)
        //把this指向新的对象，执行函数
  const result = constructor.apply(newObject, arguments)
        //判断构造函数是否返回引用对象，有则返回这个对象，没有则返回新的对象
  flag = result&&(typeof result === 'function' || typeof result === 'object')
  return flag ? result : newObject
}
function Foo(name) {
  this.name = name
}
Foo.prototype.play = function() {
  console.log(this.name + 'playing');
}
const obj = newPolyfill(Foo,'小明')
obj.play()