//实现new关键字的函数
function Person(name,age){
this.name = name
this.age = age
}
function _new(){
let func1 = [].shift.call(arguments)
let o = {}
o._proto_ = func1.prototype
let obj = func1.apply(o,arguments)
return (typeof obj == Object)?obj:o
}
let s = _new(Person,"zhao",20)
console.log(s._proto_ == Person.prototype)