call方法的实现
Function.prototype.MyCall = function(content,...args){
const self = content || window;
const args = args.slice(1)
const self.fn = this
const result = self.fn(args)
delete self.fn
return result
}
apply方法实现,和call方法差不多
Function.prototype.MyApply = function(content,args = []){
const self = content || window
self.fn = this;
let result = null
if(args.length > 0){
const = self.fn(args)
}else {
result = self.fn()
}
delete self.fn
return result
}
稍显麻烦的bind方法
Function.prototype.MyBind = function(content){
const self = this
const args = arguments.slice(1)
return function F(){
if(this instanceof F){ //通过new的方式
return new self(...args,...arguments)
}else{
const doubleArgs = args.concat(arguments)
return self.apply(content,doubleArgs)
}
}
}