configure.md

Configuring

Stylelint expects a configuration object, and looks for one in a:

• stylelint.config.js or .stylelintrc.js file
  • Which module system to use depends on your default module system configuration for Node.js (e.g., "type": "module" in package.json).
• stylelint.config.mjs or .stylelintrc.mjs file using export default (ES module)
• stylelint.config.cjs or .stylelintrc.cjs file using module.exports (CommonJS)
• .stylelintrc.json, .stylelintrc.yml, or .stylelintrc.yaml file
• .stylelintrc file in JSON or YAML format
  • We recommend adding an extension (e.g., .json) to help your editor provide syntax checking and highlighting.
• stylelint property in package.json

ES module example:

/** @type {import('stylelint').Config} */
export default {
  rules: {
    "block-no-empty": true
  }
};

Note

The @type JSDoc annotation enables Typescript to autocomplete and type-check.

CommonJS example:

module.exports = {
  rules: {
    "block-no-empty": true
  }
};

JSON example:

{
  "rules": {
    "block-no-empty": true
  }
}

Starting from the current working directory, Stylelint stops searching when one of these is found. Alternatively, you can use the --config or configFile option to short-circuit the search.

The configuration object has the following properties:

rules

Rules determine what the linter looks for and complains about. There are over 100 rules built into Stylelint. No rules are turned on by default.

The rules property is an object whose keys are rule names and values are rule configurations. For example:

{
  "rules": {
    "color-no-invalid-hex": true
  }
}

Each rule configuration fits one of the following formats:

• null (to turn the rule off)
• a single value (the primary option)
• an array with two values ([primary option, secondary options])

Specifying a primary option turns on a rule.

Many rules provide secondary options for further customization. To set secondary options, use a two-member array. For example:

{
  "rules": {
    "selector-pseudo-class-no-unknown": [
      true,
      {
        "ignorePseudoClasses": ["global"]
      }
    ]
  }
}

You can add any number of keys to the object. For example, you can:

• turn off block-no-empty
• turn on unit-allowed-list with a primary option
• turn on alpha-value-notation with a primary and secondary option

{
  "rules": {
    "block-no-empty": null,
    "unit-allowed-list": ["em", "rem", "%", "s"],
    "alpha-value-notation": ["percentage", { "exceptProperties": ["opacity"] }]
  }
}

Some rules and options accept regex. You can enforce these common cases:

• kebab-case: ^([a-z][a-z0-9]*)(-[a-z0-9]+)*$
• lowerCamelCase: ^[a-z][a-zA-Z0-9]+$
• snake_case: ^([a-z][a-z0-9]*)(_[a-z0-9]+)*$
• UpperCamelCase: ^[A-Z][a-zA-Z0-9]+$

Or enforce a prefix using a positive lookbehind regex. For example, (?<=foo-) to prefix with foo-.

disableFix

You can set the disableFix secondary option to disable autofix on a per-rule basis.

For example:

{
  "rules": {
    "color-function-notation": ["modern", { "disableFix": true }]
  }
}

message

You can use the message secondary option to deliver a custom message when a rule is violated.

For example, the following rule configuration would substitute in custom messages:

{
  "rules": {
    "custom-property-pattern": [
      "^([a-z][a-z0-9]*)(-[a-z0-9]+)*$",
      {
        "message": "Expected custom property name to be kebab-case"
      }
    ]
  }
}

Alternately, you can write a custom formatter for maximum control if you need serious customization.

Experimental feature: some rules support message arguments. For example, when configuring the color-no-hex rule, the hex color can be used in the message string:

Via JavaScript:

export default {
  rules: {
    "color-no-hex": [
      true,
      {
        message: (hex) => `Don't use hex colors like "${hex}"`
      }
    ]
  }
};

Via JSON:

{
  "rules": {
    "color-no-hex": [
      true,
      {
        "message": "Don't use hex colors like \"%s\""
      }
    ]
  }
}

With formats that don't support a function like JSON, you can use a printf-like format (e.g., %s). On the other hand, with JS format, you can use both a printf-like format and a function.

url

You can use the url secondary option to provide a custom link to external docs. These urls can then be displayed in custom formatters.

For example:

{
  "rules": {
    "color-no-hex": [true, { "url": "https://example.org/your-custom-doc" }]
  }
}

reportDisables

You can set the reportDisables secondary option to report any stylelint-disable comments for this rule, effectively disallowing authors to opt-out of it.

For example:

{
  "rules": {
    "color-no-invalid-hex": [true, { "reportDisables": true }]
  }
}

The report is considered to be a lint error.

severity

You can use the severity secondary option to adjust any specific rule's severity.

The available values for severity are:

• "warning"
• "error" (default)

For example:

{
  "rules": {
    "number-max-precision": [
      2,
      {
        "ignoreUnits": ["em"],
        "severity": "warning"
      }
    ]
  }
}

Reporters may use these severity levels to display problems or exit the process differently.

Experimental feature: some rules support message arguments. For these rules, it is possible to use a function for severity, which would accept these arguments, allowing you to adjust the severity based on these arguments.

This function must return "error", "warning", or null. When it would return null, the defaultSeverity would be used.

For example, given:

export default {
  rules: {
    "selector-disallowed-list": [
      ["a > .foo", "/\\[data-.+]/"],
      {
        severity: (selector) => {
          return selector.includes("a > .foo") ? "error" : "warning";
        }
      }
    ]
  }
};

The following pattern is reported as an error:

a > .foo {}

But the following pattern would be reported as a warning:

a[data-auto="1"] {}

extends

You can extend an existing configuration (whether your own or a third-party one). Configurations can bundle plugins, custom syntaxes, options, and configure rules. They can also extend other configurations.

For example, stylelint-config-standard is one of our official configs that you can extend.

When one configuration extends another, it starts with the other's properties and then adds to and overrides what's there.

For example, to extend the stylelint-config-standard and then change the alpha values to numbers and turn off the selector-class-pattern rule:

{
  "extends": "stylelint-config-standard",
  "rules": {
    "alpha-value-notation": "number",
    "selector-class-pattern": null
  }
}

You can extend an array of existing configurations, with each item in the array taking precedence over the previous item (so the second item overrides rules in the first, the third item overrides rules in the first and the second, and so on, the last item overrides everything else).

For example, with stylelint-config-standard, then layer myExtendableConfig on top of that, and then override the alpha-value-notation rule:

{
  "extends": ["stylelint-config-standard", "./myExtendableConfig"],
  "rules": {
    "alpha-value-notation": "number"
  }
}

The value of "extends" is a "locater" (or an array of "locaters") that is ultimately require()d. It can fit whatever format works with Node's require.resolve() algorithm. That means a "locater" can be:

• the name of a module in node_modules (e.g. stylelint-config-standard; that module's main file must be a valid JSON configuration)
• an absolute path to a file (which makes sense if you're creating a JS object in a Node.js context and passing it in) with a .js or .json extension.
• a relative path to a file with a .js or .json extension, relative to the referencing configuration (e.g. if configA has extends: "../configB", we'll look for configB relative to configA).

You'll find more configs in Awesome Stylelint.

plugins

Plugins are custom rules or sets of custom rules built to support methodologies, toolsets, non-standard CSS features, or very specific use cases.

For example, stylelint-order is a popular plugin pack to order things like properties within declaration blocks.

Plugins are often included within shared configs that you can extend. For example, the stylelint-config-standard-scss config includes the stylelint-scss plugin.

To use a plugin directly, add a "plugins" array to your config, containing either plugin objects or "locaters" identifying the plugins you want to use. As with extends, above, a "locater" can be either a:

• npm module name
• absolute path
• path relative to the invoking configuration file

Once the plugin is declared, within your "rules" object you'll need to add options for the plugin's rule(s), just like any standard rule. Look at the plugin's documentation to know what the rule name should be.

{
  "plugins": ["../special-rule.js"],
  "rules": {
    "plugin-namespace/special-rule": "everything"
  }
}

A "plugin" can provide a single rule or a set of rules. If the plugin you use provides a set, invoke the module in your "plugins" configuration value, and use the rules it provides in "rules". For example:

{
  "plugins": ["../some-rule-set.js"],
  "rules": {
    "some-rule-set/first-rule": "everything",
    "some-rule-set/second-rule": "nothing",
    "some-rule-set/third-rule": "everything"
  }
}

You'll find more plugins in Awesome Stylelint.

customSyntax

Specify a custom syntax to use on your code. More info.

overrides

Using the overrides property, you can specify what subset of files to apply a configuration to.

For example, to use the:

• postcss-scss syntax for all .scss files
• percentage notation for all alpha values in all .css files in the components and pages directories

{
  "rules": {
    "alpha-value-notation": "number"
  },
  "overrides": [
    {
      "files": ["*.scss", "**/*.scss"],
      "customSyntax": "postcss-scss"
    },
    {
      "files": ["components/**/*.css", "pages/**/*.css"],
      "rules": {
        "alpha-value-notation": "percentage"
      }
    }
  ]
}

The value of the overrides property is an array of objects. Each object:

• must contain a files property, which is an array of glob patterns that specify which files the configuration should be applied to
• should contain at least one other regular configuration property, such as customSyntax, rules, extends, etc.

The customSyntax property will be replaced, whereas plugins, extends, rules, etc. will be appended.

Patterns are applied against the file path relative to the directory of the config file. For example, if your config file has the path /project-foo/.stylelintrc.js and the file you want to lint has the path /project-foo/components/bar.css, then the pattern provided in .stylelintrc.js will be executed against the relative path components/bar.css.

Overrides have higher precedence than regular configurations. Multiple overrides within the same config are applied in order. That is, the last override block in a config file always has the highest precedence.

processors

Warning

This is an experimental feature. The API may change in the future.

This processors property was removed in 15.0.0, but has revived for post-processing. Note that this is different from the previous behavior.

Processors are functions that hook into Stylelint's pipeline. Currently, processors contains only two properties: a string name and a function postprocess. postprocess runs after all rules have been evaluated. This function receives the result object of the linting process and can modify it.

For example, you can use a processor to remap the result location. Below processor expands the warning location for 'color-no-hex' rule to the entire CSS declaration. A warning for a hex color in a rule like a { color: #111; } would originally point to the hex color itself (e.g., line 1, columns 12-16). After processing, the warning will encompass the entire declaration (e.g., line 1, columns 5-16).

{
  "rules": { "color-no-hex": true },
  "processors": ["path/to/my-processor.js"]
}

// my-processor.js

/** @type {import("stylelint").Processor} */
export default function myProcessor() {
  return {
    name: "remap-color-no-hex",

    postprocess(result, root) {
      const updatedWarnings = result.warnings.map((warning) => {
        if (warning.rule !== "color-no-hex") {
          return warning;
        }

        let updatedWarning = { ...warning };

        root?.walk((node) => {
          const { start, end } = node.source;

          if (
            node.type === "decl" &&
            start.line <= warning.line &&
            end.line >= warning.endLine &&
            start.column <= warning.column &&
            end.column >= warning.endColumn
          ) {
            updatedWarning = {
              ...updatedWarning,
              line: start.line,
              endLine: end.line,
              column: start.column,
              endColumn: end.column
            };

            return false;
          }
        });

        return updatedWarning;
      });

      result.warnings = updatedWarnings;
    }
  };
}

defaultSeverity

You can set the default severity level for all rules that do not have a severity specified in their secondary options. For example, you can set the default severity to "warning":

{
  "defaultSeverity": "warning"
}

report*

These report* properties provide extra validation for stylelint-disable comments. This can help enforce useful and well-documented disables.

The available reports are:

• reportDescriptionlessDisables
• reportInvalidScopeDisables
• reportNeedlessDisables

They are configured like rules. They can have one of three values:

• null (to turn the configuration off)
• true or false (the primary option)
• an array with two values ([primary option, secondary options])

The following secondary options are available:

• "except" takes an array of rule names for which the primary option should be inverted.
• "severity" adjusts the level of error emitted for the rule, as above.

For example, this produces errors for needless disables of all rules except selector-max-type:

{
  "reportNeedlessDisables": [true, { "except": ["selector-max-type"] }]
}

And this emits warnings for disables of unit-allowed-list that don't have a description:

{
  "reportDescriptionlessDisables": [
    false,
    {
      "except": ["unit-allowed-list"],
      "severity": "warning"
    }
  ]
}

reportDescriptionlessDisables

Report stylelint-disable comments without a description. A report* property.

For example:

{
  "reportDescriptionlessDisables": true
}

More info.

reportInvalidScopeDisables

Report stylelint-disable comments that don't match rules that are specified in the configuration object. A report* property.

For example:

{
  "reportInvalidScopeDisables": true
}

More info.

reportNeedlessDisables

Report stylelint-disable comments that don't match any lints that need to be disabled. A report* property.

For example:

{
  "reportNeedlessDisables": true
}

More info.

configurationComment

You can set what configuration comments like /* stylelint-disable */ start with. This can be useful if you use multiple instances of Stylelint with different configurations.

For example, to have an instance of Stylelint disable rules with /* stylelint-foo-instance-disable */ instead of the default /* stylelint-disable */:

{
  "configurationComment": "stylelint-foo-instance"
}

ignoreDisables

Ignore stylelint-disable (e.g. /* stylelint-disable block-no-empty */) comments.

For example:

{
  "ignoreDisables": true
}

More info.

ignoreFiles

You can provide a glob or array of globs to ignore specific files.

For example, you can ignore all JavaScript files:

{
  "ignoreFiles": ["**/*.js"]
}

Stylelint ignores the node_modules directory by default. However, this is overridden if ignoreFiles is set.

If the globs are absolute paths, they are used as is. If they are relative, they are analyzed relative to

• configBasedir, if it's provided;
• the config's filepath, if the config is a file that Stylelint found and loaded;
• or process.cwd().

Note

This is not an efficient method for ignoring lots of files. If you want to ignore a lot of files efficiently, use .stylelintignore or adjust your files globs.

allowEmptyInput

Stylelint does not throw an error when the glob pattern matches no files.

For example:

{
  "allowEmptyInput": true
}

Note

This config option should not be overridden on a per-file basis.

More info.

cache

Store the results of processed files so that Stylelint only operates on the changed ones.

For example:

{
  "cache": true
}

Note

This config option should not be overridden on a per-file basis.

More info.

fix

Automatically fix, where possible, problems reported by rules.

For example:

{
  "fix": true
}

Note

This config option should not be overridden on a per-file basis.

More info.