SOURCE

Function.prototype.myCall = function(context){
    if(typeof this !== 'function'){
        throw new TypeError('Error')
    }
    context = context || window
    context.fn = this //this为原本的方法
    const args = [...arguments].slice(1) //获取传入的参数 去除context
    const res =  context.fn(args.toString())
    delete context.fn
    return res
}

//apply类似处理一下数据就好

//bind


Function.prototype.myBind = function(context){
    if(typeof this !== 'function'){
        throw new TypeError('Error')
    }
    const _this = this
    const args = [...arguments].slice(1) //获取传入的参数 去除context
    return function F(){
        //如果调用bind是new func.myBind()的形式 
        if(this instanceof F){
            return new _this(...args,...arguments)
        }
        return _this.apply(context,args.concat(...arguments) )
    }
    
    
}