是否可以使用JavaScript中的对象字面量定义一个动态命名的属性？ [英] Is it possible to define a dynamically named property using object literal in JavaScript?

问题描述

请考虑以下

var a = {foo: "bar"};

等同于

var a = {};
a.foo = "bar";

等同于

var a = {};
a['foo'] = "bar";

等同于

var a = {}
var b = "foo";
a[b] = "bar";

是否可以执行

Is it possible to do something like

var b = "foo";
var a = { [b]: "bar" };

这样结果将是

// => {foo: "bar"}

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可接受的解决方案in JavaScript或CoffeeScript

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Acceptable solutions are in JavaScript or CoffeeScript

推荐答案

ES6支持计算属性。

ES6 supports computed properties.

// code from my original question now works in ES6 !
let b = "foo";
let a = { [b]: "bar" };

a.foo; //=> "bar"

任何表达式都可以在 [] 定义属性名称

Any expression can be used within the [] to define the property name

let a = {
  [(xs => xs.join(''))(['f','o','o'])]: 'bar'
};

a.foo; //=> "bar"

如果您需要在ES5世界中依赖这种行为，非常有能力 babel.js 将您的ES6代码转换为兼容ES5的代码。

If you need to rely on this behavior in an ES5 world, you can lean on the very capable babel.js to transpile your ES6 code to ES5-compatible code.

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