javascript - 因为它可以访问外部对象

Question

我正在尝试执行一小段代码并查看。我得到以下结果。对每个结果给出解释。你们能告诉我它是否正确吗？

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();


outer func:  this.foo = bar ------------> since it has access to outside object
outer func:  self.foo = bar ------------> since it has access to outside object
inner func:  this.foo = undefined ------------> dont know why its undefined
inner func:  self.foo = bar ------------> since it has access to variable self

Answer 1

它在内部函数中是未定义，因为它在自调用函数 中。在自调用函数中，this 的值成为 window 全局对象。因此，由于 window.foo 未定义，this.foo 也未定义，因为 this === window 在该内部函数中。