Babel 6预设的顺序是否重要？ [英] Does the order of Babel 6 presets matter?

问题描述

当我列出预设时，订单是否重要？

When I list the presets, does the order matter?

换句话说，是以下 .babelrc 等价文件？

In other words, are the following .babelrc files equivalent?

.babelrc ＃1

{
  "presets": ["es2015", "stage-2", "react"]
}

.babelrc ＃2

{
  "presets": ["react", "stage-2", "es2015"]
}

推荐答案

来自 babeljs.io/docs/plugins：（截至2016年9月30日）

From babeljs.io/docs/plugins: (as of 9/30/2016)

对插件中的每个访问者进行排序。这意味着如果两个变换都访问Program，则变换将以插件或预设顺序运行。

Ordering matters for each visitor in the plugin. This means if two transforms both visit "Program", the transforms will run in either plugin or preset order.

"plugins": [
  "transform-decorators-legacy", // will run first
  "transform-class-properties" // will run second
]

预设顺序相反（从最后到第一个）。

是的这令人困惑，请参阅 babel / notes＃2 。

我认为（对于向后兼容性）的原因是大多数用户首先列出es2015和0秒。而且-0阶段将在2015年之前运行。

I believe the reason why (for backwards compatability) is that most users had listed "es2015" first and "stage-0" second. And stage-0 would run before es2015.

"presets": [
  "es2015", // will run third
  "react", // will run second
  "stage-2" // will run first
]

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