如何将普通对象转换为 ES6 Map? [英] How to convert a plain object into an ES6 Map?

问题描述

出于某种原因，我在 MDN 文档中找不到这个简单的东西(也许我只是想念它).

For some reason I can't find this simple thing in the MDN docs (maybe I'm just missing it).

我希望这能奏效:

const map = new Map({foo: 'bar'});

map.get('foo'); // 'bar'

...但第一行抛出 TypeError: (var)[Symbol.iterator] is not a function

如何从普通对象制作地图?我真的必须先将其转换为键值对数组的数组吗?

How do I make a Map from a plain object? Do I really have to first convert it into an array of arrays of key-value pairs?

推荐答案

是的，Map 构造函数采用键值对数组.

Yes, the Map constructor takes an array of key-value pairs.

Object.entries 是 ES2017 (19.1.2.5).

const map = new Map(Object.entries({foo: 'bar'}));

map.get('foo'); // 'bar'

目前已在 Firefox 46+ 和 Edge 14+ 及更新版本中实现Chrome 版本

如果您需要支持较旧的环境并且转译不适合您，请使用 polyfill，例如 georg 推荐的:

If you need to support older environments and transpilation is not an option for you, use a polyfill, such as the one recommended by georg:

Object.entries = typeof Object.entries === 'function' ? Object.entries : obj => Object.keys(obj).map(k => [k, obj[k]]);

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