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What usually happens once people start using Prettier is that they realize how much time and mental energy they actually spend formatting their code. No matter how incomplete or broken the code you're working on is, with the Prettier Editor Extension you can always just press theFormat Document key binding and *poof*, the code snaps right into place.

• Beautiful, uniform and consistent — Prettier is strongly opinionated, with no style options.
• There when you need it the most — Prettier can format code that won't compile(e.g. missing annotations)
• Speed up the day-to-day — Prettier auto-fixes common syntax errors(e.g. missing semicolons, blocks, parentheses)

constLEET =1337/// My WIP code draft#![feature(crate_visibility_modifier)]asynccratefnfoo(arg){  arg.0 *=3.14 +LEET&1337  arg.1(|b, c| ->T&c).await}

constLEET =1337;#![feature(crate_visibility_modifier)]/// My WIP code draftcrateasyncfnfoo(arg){    arg.0 *=(3.14 +LEET)&1337;(arg.1)(|b, c| ->T{&c}).await}

https://prettier.io/docs/en/configuration

// .prettierrc.json{"useTabs":false,"tabWidth":4,"printWidth":100,"endOfLine":"lf",// -- Not supported yet --// "trailingComma": "es5",// "embeddedLanguageFormatting": "auto",// Example override"overrides":{"files":["tests/*.rs"],"options":{"printWidth":80}}}

# .prettierrc.tomluseTabs =falsetabWidth =4printWidth =100endOfLine ="lf"# -- Not supported yet --# trailingComma = "es5"# embeddedLanguageFormatting = "auto"# Example overrideoverrides = [  {files = ["tests/*.rs"],options = {printWidth =80 } }]

• Add// prettier-ignore or#[rustfmt::skip] above it
• Add#![rustfmt::skip] inside blocks or files
• Create a.prettierignore file to glob-match files, like.gitignore

• Curlies!{} format like blocks,![] and!() like comma-separated expressions
• Formatting inside macro invocations is more conservative, since macros can be token-sensitive
• Popular/built-in macros with original syntax rules get custom formatting (e.g.matches!,if_chains!...)[Not implemented yet]
• Macro Declarations are only partially formatted (the transformed part isn't yet, but could be in the future)
• Macros that can't be formatted are silently ignored

Yes! Prettier Rust formats most nightly features. Support depends onjinx-rust.

• Recommended Extension Standalone

  Easy install + auto-updates

  • VSCode | Search and installPrettier - Code formatter (Rust)[direct link]

  • Request your favorite editor:[file an issue]

• Alternative Core Extension Plugin

  RequiresNodeJS +Prettier Extension (built-in Jetbrains IDEs)

  npm install --global prettier-plugin-rust prettier

  Restart IDE after installing.
  To update (manual only!!):npm upgrade --global prettier-plugin-rust prettier
  To check installed version:npm ls -g --depth=0 prettier-plugin-rust prettier
  To check latest version:npm info prettier-plugin-rust version

• Command line

  RequiresNodeJS

  • Installprettier andprettier-plugin-rust globally

    npm install --global prettier-plugin-rust prettier

  • Use theprettier CLI to format rust files. E.g. run:

    prettier --write**/*.rs

• NodeJS package

  RequiresNodeJS

  • Installprettier andprettier-plugin-rust in the project

    npm install --save-dev prettier-plugin-rust prettier

  • Link to the plugin's location in your prettier config:

    "plugins": ["./node_modules/prettier-plugin-rust"]

  • Use theprettier CLI to format rust files. E.g. run:

    npx prettier --write**/*.rs

  • You can also use the plugin programmatically:

    importprettierfrom"prettier";import*asrustPluginfrom"prettier-plugin-rust";prettier.format(code,{plugins:[rustPlugin]});

• Rust crate

  No crate yet. Above options are available in the meantime.

• Why would I use this and not the establishedcargo fmt ?

  It's all about the Editor Integration — Having the ability to format your code while you work on it really makes for a great developer experience, and autocompletion for Rust's strict syntax is such a massive time save. Once you've tried the extension there really is no coming back.

  All-in-all the difference in code style is minimal, so adopting Prettier Rust won't drastically change your codebase. The real downside is the harsher integration with the Rust ecosystem, but it'll get better eventually.

  Point by point:

  • the extension streamlines your work in the editor
    • it can format code that won't compile(e.g. code with missing type annotations)
    • it autocorrects syntax errors(e.g. missing semicolons, blocks, parentheses...)
  • it is strongly opinionated with no style options, so code is uniform across projects.
  • it produces more readable code in some cases (e.g. condition chains, compound expressions, patterns)
  • it supports everything out-of-the-box (e.g. nightly features, macros)
  • it consistently prints code in the same way, whereas Rustfmt preserves arbitrary style at places
  • it can be used for other languages (e.g. markdown, html, typescript, java, python, ruby)
  • it formats language embeds. So rust code blocks in non-rust files (e.g. markdown), and supported languages in rust doc comments.[NOTE: the latter is not yet implemented]

• Why not just add those features to rustfmt instead?

  Unfortunately Rustfmt cannot implement those features by design.

  Rustfmt parses code with rustc. Rustc is strict and unforgiving as it always assumes code is at its "final version", thus every slight deviation from the accepted syntax crashes the parser. There's also that rustc has many lint-like checks within the parser. The intention is to save work for the compiler down the line, unfortunately it also means that rustc sometimes fails to parse syntactically correct code.

  Prettier Rust however is based onjinx-rust. Jinx-rust is built specifically for Rust tooling. Hence it's designed to tolerate a wide range of syntax errors, supports missing nodes and sometimes even infers user intent (e.g. Javascript's!==)

  Jinx-rust has a littleplaidoyer in its readme arguing for Rust Toolingnot to use the official rustc parserhere.

• When exactly does Prettier Rust change code syntax?

  The Prettier Rust syntax autocorrection feature is intended to be an adaptation of how Prettier Typescript autocorrects javascript code with missing semicolons.

  You can effectively think of Prettier Rust syntax autocorrection as auto-applying the Rust compiler's suggested syntax fixes automatically (e.g. "semicolon missing here", "parenthesize this" or "add a block around that")

  Otherwise if your codebase compiles, then Prettier Rust is just a formatter like any other. It won't change the syntax of valid rust code. Moreover, it doesn't reorganize imports, split comments or combine attributes.

• This is an "opinionated formatter". But it's brand new! How reliable are those opinions?

  Rest assured, Prettier Rust actually does not take style decisions on its own. Prettier Rust is essentially a 1:1 adaptation of Prettier Typescript, hence the opinions it implements have been battle tested and agreed-upon bymillions and millions of users already.