为什么 IIFE/函数不能访问“this"?在外部功能? [英] Why can't IIFE/function access "this" in outer function?

问题描述

在下面的代码中，

var myObject = {
    foo: "bar",
    func: function() {
        var self = this;
        console.log("outer func:  this.foo = " + this.foo);
        console.log("outer func:  self.foo = " + self.foo);
        (function() {
            console.log("inner func:  this.foo = " + this.foo);
            console.log("inner func:  self.foo = " + self.foo);
        }());
    }
};
myObject.func();

它在控制台打印:

outer func:  this.foo = bar
outer func:  self.foo = bar
inner func:  this.foo = undefined
inner func:  self.foo = bar

前两个很明显，但我不明白第三个和第四个，为什么 IIFE 可以访问 self 但没有访问权限?我认为它创建了一个闭包，因此它可以访问外部变量 self 和 this ?

The first two are pretty obvious, but I don't understand for the third and fourth one, why does the IIFE has access to self but doesn't have the access for this? I thought it creates a closure so it has access to the outer variables self and this ?

推荐答案

我不确定这是否能解决您的问题，但是您可以通过将 this 作为参数传递给 IIFE 来绑定它:

I'm not certain that this solves your problem, but you can bind this by passing it as an argument to the IIFE:

(function(context) {
    console.log("inner func:  context.foo = " + context.foo);
    console.log("inner func:  self.foo = " + self.foo);
}(this));

小提琴

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