在JavaScript中推理函数语句(Reasoning about function statements in JavaScript)

在JavaScript中推理函数语句(Reasoning about function statements in JavaScript)

请考虑以下代码：

function f() { function Ctor() {} return { instance: new Ctor(), referenceToCtor: Ctor }; } var a = f(); var b = f(); a.instance instanceof a.referenceToCtor; // true b.instance instanceof a.referenceToCtor; // false

这告诉我们关于instanceof和函数语句的含义是什么？

这是否意味着每次调用f都会实例化一个名为Ctor全新Function-object，因此instanceof返回false 。

这类似于instanceof Array和多个窗口的问题吗？

Consider the following code:

function f() { function Ctor() {} return { instance: new Ctor(), referenceToCtor: Ctor }; } var a = f(); var b = f(); a.instance instanceof a.referenceToCtor; // true b.instance instanceof a.referenceToCtor; // false

What does this tell us about the meaning of instanceof and function statements?

Does this mean that each time f is invoked a completely new Function-object named Ctor is instantiated and hence instanceof returns false.

Is this similar to the problems of instanceof Array and multiple windows?

最满意答案

这是否意味着每次调用f都会实例化一个名为Ctor全新Function-object，因此instanceof返回false 。

是。

这类似于instanceof Array和多个窗口的问题吗？

是。

Does this mean that each time f is invoked a completely new Function-object named Ctor is instantiated and hence instanceof returns false.

Yes.

Is this similar to the problems of instanceof Array and multiple windows?

Yes.