javascript - 如何使ajax里的this指向不改变

Question

var obj = {
        init:function(){
            this.ajax();
        },
        name:function(){
            console.log('123')
        },
        ajax:function(){
               //var _this = this; 不要这种方法，我想要用改变this指向的方法
             $.ajax({ 
                url:'http://www.test3.com/Main/isCookie',
                method:'GET',
                dataType:"jsonp",
                jsonp:'jsoncallback',
                jsonpCallback:'vv',
                success:function(){
                    console.log( this.name() )  //123
                }
            })
             
        }
    }
    obj.init();

如何让我在ajax里的this指向指到obj上?

Answer 1

1. @Gemini 提供的方法方法很好哦~~

2. 可以使用Function的bind方法来绑定context上下文

3. 如果不支持bind方法，那么可以简单模拟个bind方法,没有考虑输入参数的合法性及bind返回函数的再次bind的情况

function _bind(orgFunc,context){
    var aArgs = Array.prototype.slice.call(arguments, 2);
    return function(){
        return orgFunc.apply(context, aArgs);
    }
}

使用方法如下

var obj = {
    init:function(){
        this.ajax();
    },
    name:function(){
        return ‘123’;
    },
    ajax:function(){
         //原生bind方法   
         /*
         var successCallback=(function(){
             console.log(this.name() )  //123
         }).bind(this);
         */
         
         //不支持原生方法的处理
         var successCallback=_bind(function(){
             console.log(this.name());  //123
         },this);
    
         $.ajax({ 
            url:'http://www.test3.com/Main/isCookie',
            method:'GET',
            dataType:"jsonp",
            jsonp:'jsoncallback',
            jsonpCallback:'vv',
            success: successCallback
        })
         
    }
 }
 obj.init();

Answer 2

http://api.jquery.com/jQuery.ajax/

Context

Type: PlainObject
This object will be the context of all Ajax-related callbacks. By default, the context is an object that represents the Ajax settings used in the call ($.ajaxSettings merged with the settings passed to $.ajax). For example, specifying a DOM element as the context will make that the context for the complete callback of a request, like so:

$.ajax({
  url: "test.html",
  context: document.body
}).done(function() {
  $( this ).addClass( "done" );
});

Answer 3

使用bind/apply/call或用es6的箭头函数编写

Answer 4

参考这个链接描述