分配为对象属性时，IIFE如何影响其中的此关键字 [英] How IIFE affects this keyword inside it when assigned as object properties

问题描述

var a={
   name:"Rhona",
   check:(function(){
          return this.name;
            })();
   }
 console.log(a.check)// This returns ""

一个空字符串我希望它返回Rhona，它没有给出undefined或null，但是一个空字符串在这里发生了什么?

An empty string I expected it to return Rhona,it didn't give undefined or null but an empty string whats going on here?

我还想知道为什么当我访问一个不存在的对象属性时，它给出未定义而不是未定义，我认识到未定义是在创建阶段赋予变量的值，执行阶段然后初始化该值，所以如果没有初始化，它保持未定义状态，所以当我访问一个对象属性时，可以说一个a.lastname不存在，不应该返回Java脚本吗?为什么不给出undefined呢?

And i also want to know why when I access an objects property which isn't there it gives undefined instead of giving not defined I recognize undefined is the value given to variables at creation phase,execution phase then initializes the value so if there is no initialization it stays undefined so when i access an object property lets say a.lastname which isn't present shouldn't java script return not defined why is it giving undefined instead?

推荐答案

您可以使用

You can use a getter to implement what you want:

var a={
   name:"Rhona",
   get check(){
          return this.name;
            }
   }

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