手写实现apply，call，bind

 

 

一些小练习，加深对this的动态绑定、闭包的掌握。都是些小demo，没有对传入的参数做很深的检测！

废话不说了，直接上代码

 

appy

 1 var name = '李世海';
 2 var obj = {
 3     name:'李虎峰'
 4 }
 5 
 6 Function.prototype.shApply = function (thisObj,argArray){
 7     var fn = this;
 8     var thisObj = (thisObj != null &&thisObj != undefined) && typeof thisObj == 'object'?thisObj:window;
 9     thisObj.fn = fn;
10     return thisObj.fn(...argArray)
11 }
12 
13 function printInfo(age,gender){
14     console.log(this.name,age,gender);
15 }
16 
17 //直接调用
18 printInfo(22,'男');
19 //使用aplly调用
20 printInfo.shApply(obj,[22,'男']);
21 
22 // Function.prototype.apply()

 

call

 1 var name = '李世海';
 2 var obj = {
 3     name:'李虎峰'
 4 }
 5 
 6 Function.prototype.shCall = function (thisObj,...argArray){
 7     var fn = this;
 8     var thisObj = (thisObj != null &&thisObj != undefined) && typeof thisObj == 'object'?thisObj:window;
 9     thisObj.fn = fn;
10     return thisObj.fn(...argArray)
11 }
12 
13 function printInfo(age,gender){
14     console.log(this.name,age,gender);
15 }
16 
17 //直接调用
18 printInfo(22,'男');
19 //使用aplly调用
20 printInfo.shCall(obj,22,'男');
21 
22 
23 // Function.prototype.call()

 

bind

 1 var name = '李世海';
 2 var obj = {
 3     name:'李虎峰'
 4 }
 5 
 6 Function.prototype.shBind = function (thisObj,...argArray){
 7     var fn = this;
 8     var thisObj = (thisObj != null &&thisObj != undefined) && typeof thisObj == 'object'?thisObj:window;
 9     thisObj.fn = fn;
10     return function(...args){
11         return thisObj.fn(...argArray,...args);   
12     }
13 }
14 
15 function printInfo(age,gender){
16     console.log(this.name,age,gender);
17 }
18 
19 //直接调用
20 printInfo(22,'男');
21 //使用bind改变函数中this的指向
22 var newPrintInfo = printInfo.shBind(obj,22,'男');
23 newPrintInfo();
24 // 分开传参
25 var newPrintInfo = printInfo.shBind(obj,22);
26 newPrintInfo('男');
27 
28 Function.prototype.bind()

 

posted @ 2021-11-23 14:10  睡成蛆  阅读(30)  评论(0)  编辑  收藏  举报