手写call,bind,apply
作者:互联网
//实现call var that = this ; //小程序环境 function mySymbol(obj){ let unique = (Math.random() + new Date().getTime()).toString(32).slice(0,8); if(obj.hasOwnProperty(unique)){ return mySymbol(obj) }else { return unique; } } let Person = { name:'Tom', say(age = 23,city = '宁波',job = '前端'){ console.log(`我叫${this.name},今年${age},在${city},从事${job}`) } } let Person1 = { name:'Tom1' } Function.prototype.MyCall = function(context){ context =context || that; //小程序环境 PC环境为context =context || window; let fn = mySymbol(context); context.fn = this; let arg = [...arguments].slice(1); context.fn(...arg); delete context.fn; } Person.say.MyCall(Person1,23,'宁波','前端'); Person.say.call(Person1,23,'宁波','前端'); //实现apply Function.prototype.myApply = function(cxt,args){ cxt = cxt||that; //小程序环境为cxt = cxt||that; PC环境为cxt = cxt||window; var fn = mySymbol(cxt); cxt[fn] = this; var result = cxt[fn](...args); return result; } Person.say.myApply(Person1,['23','宁波','前端']) Person.say.apply(Person1,['23','宁波','前端']) Function.prototype.myBind = function(context){ let self = this; let arg = [...arguments].slice(1); return function(){ let newArg = [...arguments]; return self.apply(context,arg.concat(newArg)) } } let fn = Person.say.myBind(Person1,23); fn(); fn('宁波','前端')
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标签:cxt,23,bind,say,call,context,apply,let,fn 来源: https://www.cnblogs.com/zwyboom/p/11791711.html