对象文字/初始化器中的自引用 [英] Self-references in object literals / initializers

问题描述

有没有办法在JavaScript中使用以下内容？

Is there any way to get something like the following to work in JavaScript?

var foo = {
    a: 5,
    b: 6,
    c: this.a + this.b  // Doesn't work
};

在当前表单中，此代码显然会引发引用错误，因为 this 不引用 foo 。但是有没有办法让对象文字的属性中的值依赖于之前声明的其他属性？

In the current form, this code obviously throws a reference error since this doesn't refer to foo. But is there any way to have values in an object literal's properties depend on other properties declared earlier?

推荐答案

<嗯，我唯一可以告诉你的是吸气剂：

Well, the only thing that I can tell you about are getters:

var foo = {
  a: 5,
  b: 6,
  get c () {
    return this.a + this.b;
  }
};

foo.c; // 11

这是ECMAScript第5版规范引入的语法扩展，语法支持大多数现代浏览器（包括IE9）。

This is a syntactic extension introduced by the ECMAScript 5th Edition Specification, the syntax is supported by most modern browsers (including IE9).

这篇关于对象文字/初始化器中的自引用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！