call方法实现
1 Function.prototype.mycall = function(context) { 2 var context = context || window 3 context.fn = this 4 var args = [...arguments].slice(1) 5 var result = context.fn(...args) 6 delete context.fn 7 return result 8 } 9 var a = {name: ‘ss‘} 10 function getName(){console.log(this.name)} 11 getName.mycall(a) // ‘ss‘
apply方法实现
Function.prototype.myapply = function(context) { var context = context || window context.fn = this var result if (arguments[1]) { result = context.fn(...arguments[1]) } else { result = context.fn() } delete context.fn return result } var a = {name: ‘ss‘} function getName(){console.log(this.name)} getName.apply(a) // ‘ss‘
bind实现
Function.prototype.myBind = function (context) { if (typeof this !== ‘function‘) { throw new TypeError(‘Error‘) } var _this = this var args = [...arguments].slice(1) // 返回一个函数 return function F() { // 因为返回了一个函数,我们可以 new F(),所以需要判断 if (this instanceof F) { return new _this(...args, ...arguments) } return _this.apply(context, args.concat(...arguments)) } }
原文地址:https://www.cnblogs.com/codejoker/p/10462278.html
时间: 2024-11-05 22:52:45