eslint-plugin-prettier

eslint-plugin-prettier

Runs Prettier as an ESLint rule and reports differences as individual ESLint issues.

If your desired formatting does not match Prettier’s output, you should use a different tool such as prettier-eslint instead.

Sample

error: Insert `,` (prettier/prettier) at pkg/commons-atom/ActiveEditorRegistry.js:22:25:
  20 | import {
  21 |   observeActiveEditorsDebounced,
> 22 |   editorChangesDebounced
     |                         ^
  23 | } from './debounced';;
  24 |
  25 | import {observableFromSubscribeFunction} from '../commons-node/event';


error: Delete `;` (prettier/prettier) at pkg/commons-atom/ActiveEditorRegistry.js:23:21:
  21 |   observeActiveEditorsDebounced,
  22 |   editorChangesDebounced
> 23 | } from './debounced';;
     |                     ^
  24 |
  25 | import {observableFromSubscribeFunction} from '../commons-node/event';
  26 | import {cacheWhileSubscribed} from '../commons-node/observable';


2 errors found.

./node_modules/.bin/eslint --format codeframe pkg/commons-atom/ActiveEditorRegistry.js (code from nuclide).

Installation

npm install --save-dev eslint-plugin-prettier
npm install --save-dev --save-exact prettier

eslint-plugin-prettier does not install Prettier or ESLint for you. You must install these yourself.

Then, in your .eslintrc.json:

{
  "plugins": ["prettier"],
  "rules": {
    "prettier/prettier": "error"
  }
}

Recommended Configuration

This plugin works best if you disable all other ESLint rules relating to code formatting, and only enable rules that detect potential bugs. (If another active ESLint rule disagrees with prettier about how code should be formatted, it will be impossible to avoid lint errors.) You can use eslint-config-prettier to disable all formatting-related ESLint rules.

This plugin ships with a plugin:prettier/recommended config that sets up both the plugin and eslint-config-prettier in one go.

1. In addition to the above installation instructions, install eslint-config-prettier:

   npm install --save-dev eslint-config-prettier
   

2. Then you need to add plugin:prettier/recommended as the last extension in your .eslintrc.json:

   {
     "extends": ["plugin:prettier/recommended"]
   }
   

   You can then set Prettier's own options inside a .prettierrc file.

3. Some ESLint plugins (such as eslint-plugin-react) also contain rules that conflict with Prettier. Add extra exclusions for the plugins you use like so:

   {
     "extends": [
       "plugin:prettier/recommended",
       "prettier/flowtype",
       "prettier/react"
     ]
   }
   

   For the list of every available exclusion rule set, please see the readme of eslint-config-prettier.

Exactly what does plugin:prettier/recommended do? Well, this is what it expands to:

{
  "extends": ["prettier"],
  "plugins": ["prettier"],
  "rules": {
    "prettier/prettier": "error",
    "arrow-body-style": "off",
    "prefer-arrow-callback": "off"
  }
}

• "extends": ["prettier"] enables the main config from eslint-config-prettier, which turns off some ESLint core rules that conflict with Prettier.
• "plugins": ["prettier"] registers this plugin.
• "prettier/prettier": "error" turns on the rule provided by this plugin, which runs Prettier from within ESLint.
• "arrow-body-style": "off" and "prefer-arrow-callback": "off" turns off two ESLint core rules that unfortunately are problematic with this plugin – see the next section.

arrow-body-style and prefer-arrow-callback issue

If you use arrow-body-style or prefer-arrow-callback together with the prettier/prettier rule from this plugin, you can in some cases end up with invalid code due to a bug in ESLint’s autofix – see issue #65.

For this reason, it’s recommended to turn off these rules. The plugin:prettier/recommended config does that for you.

You can still use these rules together with this plugin if you want, because the bug does not occur all the time. But if you do, you need to keep in mind that you might end up with invalid code, where you manually have to insert a missing closing parenthesis to get going again.

If you’re fixing large of amounts of previously unformatted code, consider temporarily disabling the prettier/prettier rule and running eslint --fix and prettier --write separately.

Options

Note: While it is possible to pass options to Prettier via your ESLint configuration file, it is not recommended because editor extensions such as prettier-atom and prettier-vscode will read .prettierrc, but won't read settings from ESLint, which can lead to an inconsistent experience.

• The first option:

  • An object representing options that will be passed into prettier. Example:

    "prettier/prettier": ["error", {"singleQuote": true, "parser": "flow"}]
    

    NB: This option will merge and override any config set with .prettierrc files

• The second option:

  • An object with the following options

    • usePrettierrc: Enables loading of the Prettier configuration file, (default: true). May be useful if you are using multiple tools that conflict with each other, or do not wish to mix your ESLint settings with your Prettier configuration.

      "prettier/prettier": ["error", {}, {
        "usePrettierrc": false
      }]
      

    • fileInfoOptions: Options that are passed to prettier.getFileInfo to decide whether a file needs to be formatted. Can be used for example to opt-out from ignoring files located in node_modules directories.

      "prettier/prettier": ["error", {}, {
        "fileInfoOptions": {
          "withNodeModules": true
        }
      }]
      

• The rule is autofixable -- if you run eslint with the --fix flag, your code will be formatted according to prettier style.

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Contributing

See CONTRIBUTING.md