JavaScript instanceof [英] JavaScript instanceof

问题描述

你能否告诉我为什么在下面的例子中超级的子实例是 false ？

Can you please tell my why in the example below sub instanceof Super is false?

function Super(){
    var obj = {
        prop1: "value1"
    };
    return obj;
}

var sub = new Super();
sub instanceof Super // false

推荐答案

因为它不是那种类型的实例 - 你已经返回了一个匿名对象。如果你这样写的话：

Because its not an instance of that type - you've returned an anonymous object. If you would have written it like this:

function Super(){
 this.prop1 = 'value1';   
}

var sub = new Super();
console.log(sub instanceof Super) // true

它可以按预期工作

这篇关于JavaScript instanceof的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！