SOURCE

//代码实现call方法
Function.prototype.myCall=function(obj,...args){
    obj._fn_ = this
    obj._fn_(...args)
    delete obj._fn_
}

//代码实现apply方法
Function.prototype.myApply=function(obj,args){
    var argms = []
    for(let i=0;i<args.length;i++){
        argms.push(args[i])
    }
  return this.myCall(obj,...argms)
}

//代码实现bind方法
Function.prototype.myBind=function(obj,...arg2){
    return (...arg3) =>{
         return this.myApply(obj, arg2.concat([...arg3]))
    }       
}


function Person(name){
    this.name=name
}

Person.prototype.sayIt=function(){
    console.log(this.name, ...arguments)
}

//组合继承
function Girl(name){
    Person.call(this, name)
}
Girl.prototype = new Person()


console.log('compile')

var roc = new Person('roc')
var girl = new Girl('Mary')

var bindGirl = roc.sayIt.myBind(girl)

console.log(bindGirl('hello','roc'))