如何使用babel 7添加flatMap？ [英] How to add flatMap using babel 7?

问题描述

阅读文章删除Babel的舞台预设通过 babel ，我仍然不完全了解如何添加提案，例如 stage-3 （ flatMap ）到 .babelrc 。

After reading the article Removing Babel's Stage Presets by babel, I still not fully understand how to add a proposal from, for example, stage-3 (flatMap) to .babelrc.

据我了解，因为 flatMap 可以用ES5编写，那么我需要一个polyfill而不是插件。我在--save-dev下安装了 @ babel / polyfill ，但浏览器仍然告诉我这个方法不存在。我想 @ babel / polyfill 不包括实验性功能。

As far as I understand, because flatMap can be written in ES5, then I need a polyfill and not a plugin. I installed @babel/polyfill under --save-dev but the browser still tells me that this method doesn't exist. I guess that @babel/polyfill doesn't cover experimental features.

推荐答案

flatMap已从@ babel / polyfill中移除给babel 7.您需要直接从core-js中包含它，例如

flatMap was removed from @babel/polyfill for babel 7. You need to include it directly from core-js, like

import "core-js/fn/array/flat-map";

或者如果你想要babel 6曾经使用的所有polyfills包括：

Or if you want all of the polyfills that babel 6 used to include:

import "core-js/shim";

参见： https://github.com/babel/babel/pull/8440 （或更直接地， v7升级指南的相关部分

See: https://github.com/babel/babel/pull/8440 (or more directly, the relevant section of the v7 upgrade guide)

（另外，不要担心必须添加一个新包：你的依赖树中已经有了core-js;这就是babel / polyfill得到的地方其余的Stage 4+ polyfills ）

(Also, don't worry about having to add a new package: you already have core-js in your dependency tree; that's where babel/polyfill gets the rest of its Stage 4+ polyfills)

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