Question

Prettier uses cosmiconfig for configuration file support. This means you can configure prettier via (in order of precedence):

• A "prettier" key in your package.json file.
• A .prettierrc file, written in JSON or YAML, with optional extensions: .json/.yaml/.yml (without extension takes precedence).
• A .prettierrc.js or prettier.config.js file that exports an object.
• A .prettierrc.toml file, written in TOML (the .toml extension is required).

The configuration file will be resolved starting from the location of the file being formatted, and searching up the file tree until a config file is (or isn't) found.

The options to the configuration file are the same as the API options.

Basic Configuration

JSON:

{
  "trailingComma": "es5",
  "tabWidth": 4,
  "semi": false,
  "singleQuote": true
}

JS:

// prettier.config.js or .prettierrc.js
module.exports = {
  trailingComma: "es5",
  tabWidth: 4,
  semi: false,
  singleQuote: true
};

YAML:

# .prettierrc or .prettierrc.yaml
trailingComma: "es5"
tabWidth: 4
semi: false
singleQuote: true

TOML:

# .prettierrc.toml
trailingComma = "es5"
tabWidth = 4
semi = false
singleQuote = true

Configuration Overrides

Overrides let you have different configuration for certain file extensions, folders and specific files.

Prettier borrows ESLint's override format.

JSON:

{
  "semi": false,
  "overrides": [
    {
      "files": "*.test.js",
      "options": {
        "semi": true
      }
    },
    {
      "files": ["*.html", "legacy/**/*.js"],
      "options": {
        "tabWidth": 4
      }
    }
  ]
}

YAML:

semi: false
overrides:
  - files: "*.test.js"
    options:
      semi: true
  - files:
      - "*.html"
      - "legacy/**/*.js"
    options:
      tabWidth: 4

files is required for each override, and may be a string or array of strings. excludeFiles may be optionally provided to exclude files for a given rule, and may also be a string or array of strings.

Sharing configurations

Sharing a Prettier configuration is simple: just publish a module that exports a configuration object, say @company/prettier-config, and reference it in your package.json:

{
  "name": "my-cool-library",
  "version": "9000.0.1",
  "prettier": "@company/prettier-config"
}

If you don't want to use package.json, you can use any of the supported extensions to export a string, e.g. .prettierrc.json:

"@company/prettier-config"

An example configuration repository is available here.

Note: This method does not offer a way to extend the configuration to overwrite some properties from the shared configuration. If you need to do that, import the file in a .prettierrc.js file and export the modifications, e.g:

module.exports = {
  ...require("@company/prettier-config"),
  semi: false
};

Setting the parser option

By default, Prettier automatically infers which parser to use based on the input file extension. Combined with overrides you can teach Prettier how to parse files it does not recognize.

For example, to get Prettier to format its own .prettierrc file, you can do:

{
  "overrides": [
    {
      "files": ".prettierrc",
      "options": { "parser": "json" }
    }
  ]
}

You can also switch to the flow parser instead of the default babel for .js files:

{
  "overrides": [
    {
      "files": "*.js",
      "options": {
        "parser": "flow"
      }
    }
  ]
}

Note: Never put the parser option at the top level of your configuration. Only use it inside overrides. Otherwise you effectively disable Prettier's automatic file extension based parser inference. This forces Prettier to use the parser you specified for all types of files – even when it doesn't make sense, such as trying to parse a CSS file as JavaScript.

Configuration Schema

If you'd like a JSON schema to validate your configuration, one is available here: http://json.schemastore.org/prettierrc.