什么是 Prettier？

Prettier 是一个有态度的代码格式化程序，支持：

¥Prettier is an opinionated code formatter with support for:

JavaScript（包括实验性功能）

¥JavaScript (including experimental features)
JSX
Angular
Vue
Flow
TypeScript
CSS、Less 和 SCSS

¥CSS, Less, and SCSS
HTML
Ember/Handlebars
JSON
GraphQL
Markdown，包括 GFM 和 MDX v1

¥Markdown, including GFM and MDX v1
YAML

它删除所有原始风格 * 并确保所有输出的代码都符合一致的风格。（见此博文）

¥It removes all original styling* and ensures that all outputted code conforms to a consistent style. (See this blog post)

Prettier 将你的代码考虑到行的长度，并从头开始重新打印它。

¥Prettier takes your code and reprints it from scratch by taking the line length into account.

例如，采用以下代码：

¥For example, take the following code:

foo(arg1, arg2, arg3, arg4);

它适合单行，因此它将保持原样。然而，我们都遇到过这种情况：

¥It fits in a single line so it’s going to stay as is. However, we've all run into this situation:

foo(reallyLongArg(), omgSoManyParameters(), IShouldRefactorThis(), isThereSeriouslyAnotherOne());

突然间，我们之前调用函数的格式就崩溃了，因为它太长了。Prettier 将为你完成重印它的艰苦工作：

¥Suddenly our previous format for calling function breaks down because this is too long. Prettier is going to do the painstaking work of reprinting it like that for you:

foo(
  reallyLongArg(),
  omgSoManyParameters(),
  IShouldRefactorThis(),
  isThereSeriouslyAnotherOne(),
);

Prettier 在整个代码库中强制执行一致的代码风格（即不会影响 AST 的代码格式），因为它通过解析原始风格 * 并使用自己的规则重新打印解析后的 AST，这些规则将最大行长度纳入其中账户，必要时封装代码。

¥Prettier enforces a consistent code style (i.e. code formatting that won’t affect the AST) across your entire codebase because it disregards the original styling* by parsing it away and re-printing the parsed AST with its own rules that take the maximum line length into account, wrapping code when necessary.

如果你想了解更多信息，这两个会议演讲是很好的介绍：

¥If you want to learn more, these two conference talks are great introductions:

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¥Footnotes

事实上，一些原始风格在实用时会被保留 - 请参阅空行和多行对象。

¥* Well actually, some original styling is preserved when practical—see empty lines and multi-line objects.

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