stylelint-declaration-strict-value

A stylelint plugin that enforces either variables ($sass, namespace.$sass, @less, var(--cssnext), css-loader @value), functions or custom CSS values, like keywords (inherit, none, currentColor etc.), colors (#fff, red, etc.) or numbers incl. units (0, 1px, 100%, etc.) for CSS longhand and experimental shorthand properties.

Table of Contents

• Installation
• Usage
  • Scheme
  • Primary Options
    • Multiple Properties
    • Regex support
  • Secondary Options
    • ignoreVariables
      • Disable variables for specific props
    • ignoreFunctions
      • Disable functions for specific props
    • ignoreValues
      • Simple single value
      • List of values
      • Complex Mighty Hash Mapping
    • ignoreKeywords (DEPRECATED)
      • Simple single keyword
      • List of keywords
      • Complex Mighty Hash Mapping
    • CSS shorthand Syntax
      • expandShorthand
      • recurseLonghand
    • message
    • Autofix support
• API
  • Credit / Inspiration
• License

Installation

npm install stylelint-declaration-strict-value

Usage

Add it to your stylelint config plugins array, then add "scale-unlimited/declaration-strict-value" to your rules, specifying the property for which you want to check the usage of variables, functions, keywords or values.

Like so:

// .stylelintrc
{
  "plugins": [
    "stylelint-declaration-strict-value"
  ],
  "rules": {
    // ...
    "scale-unlimited/declaration-strict-value": "color",
    // ...
  }
}

The following patterns are considered warnings:

a { color: #FFF; }

a { color: inherit; }

a { color: currentColor; }

The following patterns are not considered warnings:

a { color: var(--color-white); }

a { color: -var(--color-white); }

a { color: color(red alpha(-10%)); }

a { color: @color-white; }

a { color: -@color-white; }

a { color: darken(#fff, 10%); }

a { color: $color-white; }

a { color: namespace.$color-white; }

a { color: -$color-white; }

a { color: darken(#fff, 10%); }

@value v-color-white: #fff;

a { color: v-color-white; }

a { color: -v-color-white; }

Scheme

The config scheme looks as follows:

[
  // primary options
  "string" || "/RegExp/[gimsuy]" || ["string", "/RegExp/[gimsuy]" /* ... */],

  // secondary options (optional)
  {
    ignoreVariables: true || false || { "color": true || false },
    ignoreFunctions: true || false || { "color": true || false },
    ignoreValues: "string" || "/RegExp/[gimsuy]" ||
      ["string", "/RegExp/[gimsuy]", /* ... */] ||
      {
        // match all
        "": "string" || "/RegExp/[gimsuy]" || ["string", "/RegExp/[gimsuy]", /* ... */],

        // match specific prop
        "color": "string" || "/RegExp/[gimsuy]" || ["string", "/RegExp/[gimsuy]", /* ... */],

        // match pattern prop
        "/RegExp/[gimsuy]": "string" || "/RegExp/[gimsuy]" || ["string", "/RegExp/[gimsuy]", /* ... */],
      },
    // DEPRECATED (use ignoreValues)
    ignoreKeywords: "string" ||
      ["string", "string", /* ... */] ||
      {
        // match all
        "": "string" || ["string", /* ... */],

        // match specific prop
        "color": "string" || ["string", /* ... */],

        // match pattern prop
        "/RegExp/[gimsuy]": "string" || ["string", /* ... */],
      },
    expandShorthand: true || false,
    recurseLonghand: true || false,
    autoFixFunc: './auto-fix-func.js' || function() {},
    disableFix: true || false,
    message: "Custom expected ${types} for \"${value}\" of \"${property}\"",
  }
]

Primary Options

Primary options represent either a single property or a list of multiple properties to check. Technically it's either a "string" or an [array] of simple strings or /RegExp/[gimsuy].

Multiple Properties

Multiple properties can be linted by passing as an array. Regex can also be used inside arrays.

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
      ["/color$/", "z-index", "font-size"]
      ],
  // ...
}

The following patterns are considered warnings:

a {
  color: #FFF;
  z-index: 1;
  font-size: 20px;
 }

a {
  color: inherit;
  z-index: auto;
  font-size: inherit;
 }

The following patterns are not considered warnings:

a {
  color: var(--color-white);
  z-index: var(--a-z-index);
  font-size: var(--a-font-size);
}

a {
  color: @color-white;
  z-index: @a-z-index;
  font-size: @a-font-size;
}

a {
  color: $color-white;
  z-index: $a-z-index;
  font-size: $a-font-size;
  line-height: namespace.$line-height;
}

@value v-color-white: #fff;
@value v-z-index: 123;
@value v-font-size: 2em;

a {
  color: v-color-white;
  z-index: v-z-index;
  font-size: v-font-size;
}

Note: Multiple Properties require you to use nested arrays [[]] in your configuration.

Regex support

Passing a regex will lint the variable usage for all matching properties, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": "/color$/",
  // ...
}

Note for JSON / YAML: Regex needs to be activated by surrounding / slashes.

The following patterns are considered warnings:

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
}

The following patterns are not considered warnings:

a {
  color: var(--color-white);
  background-color: var(--color-white);
  border-color: var(--color-white);
}

a {
  color: @color-white;
  background-color: @color-white;
  border-color: @color-white;
}

a {
  color: $color-white;
  background-color: $color-white;
  border-color: $color-white;
}

a {
  color: namespace.$color-white;
  background-color: namespace.$color-white;
  border-color: namespace.$color-white;
}

@value v-color-white: #fff;

a {
  color: v-color-white;
  background-color: v-color-white;
  border-color: v-color-white;
}

Secondary Options

Additionally you can pass an optional second options hash to enable/disable variables, functions and custom keywords.

The default config is:

// defaults
{
  ignoreVariables: true,
  ignoreFunctions: true,
  ignoreValues: null,
  // DEPRECATED (use ignoreValues)
  ignoreKeywords: null,
}

ignoreVariables

Variables can be enabled or disabled, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": ["/color$/", {
    ignoreVariables: false,
  }],
  // ...
}

The following patterns are considered warnings:

a { color: var(--color-white); }

a { color: @color-white; }

a { color: $color-white; }

a { color: namespace.$color-white; }

@value v-color-white: #fff;

a { color: v-color-white; }

The following patterns are not considered warnings:

a { color: color(red alpha(-10%)); }

a { color: darken(#fff, 10%); }

a { color: darken(#fff, 10%); }

Disable variables for specific props

Variables can be enabled for all props, except those listed in a hash, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [["/color$/", "margin"], {
    ignoreVariables: {
      "margin": false,
    },
  }],
  // ...
}

The following patterns are considered warnings:

a { margin: var(--margin); }

a { margin: @margin; }

a { margin: $margin; }

a { margin: namespace.$margin; }

@value v-margin: 10px;

a { margin: v-margin; }

The following patterns are not considered warnings:

a { color: var(--color-white); }

a { color: @color-white; }

a { color: $color-white; }

a { color: namespace.$color-white; }

@value v-color-white: #fff;

a { color: v-color-white; }

ignoreFunctions

Functions can be enabled or disabled, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": ["/color$/", {
    ignoreFunctions: false,
  }],
  // ...
}

The following patterns are considered warnings:

a { color: color(red alpha(-10%)); }

a { color: darken(#fff, 10%); }

a { color: darken(#fff, 10%); }

The following patterns are not considered warnings:

a { color: var(--color-white); }

a { color: @color-white; }

a { color: $color-white; }

a { color: namespace.$color-white; }

Disable functions for specific props

Functions can be enabled for all props, except those listed in a hash, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [["/color$/", "margin"], {
    ignoreFunctions: {
      "margin": false,
    },
  }],
  // ...
}

The following patterns are considered warnings:

a { margin: calc(10% - 5px); }

a { margin: ceil(4.9); }

a { margin: math.ceil(4.9); }

The following patterns are not considered warnings:

a { color: color(red alpha(-10%)); }

a { color: darken(#fff, 10%); }

a { color: darken(#fff, 10%); }

ignoreValues

This allows you to ignore any CSS value like:

• keywords currentColor, inherit, transparent, etc.
• units 0, 10px, 1em, 100%, etc.
• colors #fff, #FFFFFF, red, etc.

This configuration can either be a simple "string", number, "/RegExp/[gimsuy]", an [array] of "strings", numbers, "/RegExp/[gimsuy]" or a complex hash of property/keyword mappings.

Simple single value

To ignore a single value for all properties simply use a "string" or "/RegExp/[gimsuy]", like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": ["/color$/", {
    ignoreValues: "currentColor",
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
}

Or with a "/RegExp/[gimsuy]" for hex colors:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": ["/color$/", {
    ignoreValues: "/^#[0-9a-fA-F]{3,6}$/",
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
}

The following patterns are not considered warnings:

a {
  color: #fff;
  background-color: #FFF;
  border-color: #FFFFFF;
}

Or with multiple properties:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
    ["/color$/", "fill", "stroke"], {
    ignoreValues: "currentColor",
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
  fill: #FFF;
  stroke: #FFF;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
  fill: inherit;
  stroke: inherit;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
  fill: currentColor;
  stroke: currentColor;
}

List of values

To ignore a list of values for all properties simply use an [array], like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": ["/color$/", {
    ignoreValues: ["currentColor", "/^#[0-9a-fA-F]{3,6}$/", "inherit"],
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: transparent;
  background-color: transparent;
  border-color: transparent;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
}

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
}

Or with multiple properties:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
    ["/color$/", "fill", "stroke"], {
    ignoreValues: ["currentColor", "/^#[0-9a-fA-F]{3,6}$/", "inherit"],
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: transparent;
  background-color: transparent;
  border-color: transparent;
  fill: transparent;
  stroke: transparent;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
  fill: currentColor;
  stroke: currentColor;
}

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
  fill: #FFF;
  stroke: #FFF;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
  fill: inherit;
  stroke: inherit;
}

Complex Mighty Hash Mapping

You may noticed that the above methods do count for all properties. In case you wish more sophisticated control {hash} based configs is the right choice for you.

The basic principle works the same as above - you either have one value or a list of values. This time you can define them for each property separately, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
    ["/color$/", "fill", "stroke"], {
    ignoreValues: {
        "/color$/": ["currentColor",  "/^#[0-9a-fA-F]{3,6}$/", "inherit"],
        "fill": ["currentColor", "inherit"],
        "stroke": "currentColor",
        "z-index":  "/^\\d+$/",
    },
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: transparent;
  background-color: transparent;
  border-color: transparent;
  fill: #FFF;
  stroke: #FFF;
  z-index: inherit;
}

a {
  fill: transparent;
  stroke: transparent;
}

a {
  stroke: inherit;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
  fill: currentColor;
  stroke: currentColor;
  z-index: 0;
}

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
  z-index: 1;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
  fill: inherit;
  z-index: 1000;
}

Note In case you still want to define a default list of allowed values, you can with the empty "" string property name, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
    ["/color$/", "fill", "stroke"], {
    ignoreValues: {
        // default, for all
        "": ["currentColor"],

        // specific mapping
        "/color$/": ["currentColor", "transparent", "inherit"],
        "fill": ["currentColor", "inherit"],
    },
  }],
  // ...
}

ignoreKeywords (DEPRECATED)

DEPRECATED: This allows you to ignore several CSS keywords like currentColor, inherit, transparent, etc. Note: for convenience also non-standard-keywords like 0 can be specified.

This configuration can either be a simple "string", number, an [array] of "strings", numbers or a complex hash of property/keyword mappings.

Simple single keyword

To ignore a single keyword for all properties simply use a "string", like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": ["/color$/", {
    ignoreKeywords: "currentColor",
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
}

Or with multiple properties:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
    ["/color$/", "fill", "stroke"], {
    ignoreKeywords: "currentColor",
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
  fill: #FFF;
  stroke: #FFF;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
  fill: inherit;
  stroke: inherit;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
  fill: currentColor;
  stroke: currentColor;
}

List of keywords

To ignore a list of keywords for all properties simply use an [array], like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": ["/color$/", {
    ignoreKeywords: ["currentColor", "transparent", "inherit"],
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
}

a {
  color: transparent;
  background-color: transparent;
  border-color: transparent;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
}

Or with multiple properties:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
    ["/color$/", "fill", "stroke"], {
    ignoreKeywords: ["currentColor", "transparent", "inherit"],
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
  fill: #FFF;
  stroke: #FFF;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
  fill: currentColor;
  stroke: currentColor;
}

a {
  color: transparent;
  background-color: transparent;
  border-color: transparent;
  fill: transparent;
  stroke: transparent;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
  fill: inherit;
  stroke: inherit;
}

Complex Mighty Hash Mapping

You may noticed that the above methods do count for all properties. In case you wish more sophisticated control {hash} based configs is the right choice for you.

The basic principle works the same as above - you either have one keyword or a list of keywords. This time you can define them for each property separately, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
    ["/color$/", "fill", "stroke"], {
    ignoreKeywords: {
        "/color$/": ["currentColor", "transparent", "inherit"],
        "fill": ["currentColor", "inherit"],
        "stroke": "currentColor",
        "z-index": 0,
    },
  }],
  // ...
}

The following patterns are considered warnings:

a {
  color: #FFF;
  background-color: #FFF;
  border-color: #FFF;
  fill: #FFF;
  stroke: #FFF;
  z-index: 1;
}

a {
  fill: transparent;
  stroke: transparent;
}

a {
  stroke: inherit;
}

The following patterns are not considered warnings:

a {
  color: currentColor;
  background-color: currentColor;
  border-color: currentColor;
  fill: currentColor;
  stroke: currentColor;
  z-index: 0;
}

a {
  color: transparent;
  background-color: transparent;
  border-color: transparent;
}

a {
  color: inherit;
  background-color: inherit;
  border-color: inherit;
  fill: inherit;
}

Note In case you still want to define a default list of allowed keywords, you can with the empty "" string property name, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
    ["/color$/", "fill", "stroke"], {
    ignoreKeywords: {
        // default, for all
        "": ["currentColor"],

        // specific mapping
        "/color$/": ["currentColor", "transparent", "inherit"],
        "fill": ["currentColor", "inherit"],
    },
  }],
  // ...
}

CSS shorthand Syntax

CSS shorthand Syntax support is disabled by default. This feature is baked by shortcss and css-values, a list of supported shorthand properties can be found at css-shorthand-properties and a list of validated CSS property/value pairs at property-support.

How this works is:

1. Try to lint a direct match
2. If no direct match, check if the prop can be expanded and check the longhand props
3. The expansion by shortcss is not 100% standard conform, i.e. assigning correct default values if you omit some longhands like text-decoration-color.
4. So CSS validity check by css-values is performed for each expanded longhand property to avoid wrong linting errors

Warning: How do you determine, which longhand property is used by using a single shorthand? Like in this example:

a {
  background: white; // this is background-color
  background: url('image.png'); // this is background-image

  text-decoration: none; // this is text-decoration-style
  text-decoration: #fff; // this is text-decoration-color
}

Differentiating this would need a CSS value parser and a curated list of valid CSS values per prop. This is beyond the scope of shortcss.

All properties that are expanded right now, can be found here: https://github.com/gilmoreorless/css-shorthand-properties/blob/master/index.js

And it becomes even trickier if you consider dynamic values such as variables or functions, like:

  background: get-bg(); // what does this function return? a longhand, or shorthand value?

  text-decoration: $text-deco; // what is behind this var? is it a longhand, or shorthand value?
  text-decoration: @text-deco; // what is behind this var? is it a longhand, or shorthand value?
}

expandShorthand

If true and if no exact property match is found, shorthand CSS properties will be expanded and checked againtst your primary options.

Let's say you want to check border-color.

You can either configure a direct longhand CSS property to match.

// .stylelintrc
{
  "plugins": [
    "stylelint-declaration-strict-value"
  ],
  "rules": {
    // ...
    "scale-unlimited/declaration-strict-value": ["border-color", { "expandShorthand": true }]
    // ...
  }
}

The following patterns are considered warnings:

a { border: 1px solid #FFF; }

a { border: 1px solid inherit; }

a { border: 1px solid currentColor; }

The following patterns are not considered warnings:

a { border: 1px solid var(--color-white); }

a { border: 1px solid -var(--color-white); }

a { border: 1px solid color(red alpha(-10%)); }

a { border: 1px solid @color-white; }

a { border: 1px solid -@color-white; }

a { border: 1px solid darken(#fff, 10%); }

a { border: 1px solid $color-white; }

a { border: 1px solid namespace.$color-white; }

a { border: 1px solid -$color-white; }

a { border: 1px solid darken(#fff, 10%); }

Or a simple regex for /color$/.

// .stylelintrc
{
  "plugins": [
    "stylelint-declaration-strict-value"
  ],
  "rules": {
    // ...
    "scale-unlimited/declaration-strict-value": ["/color$/", { "expandShorthand": true }]
    // ...
  }
}

The following patterns are considered warnings:

a { border: 1px solid #FFF; }

a { border: 1px solid inherit; }

a { border: 1px solid currentColor; }

a { color: #FFF; }

a { color: inherit; }

a { color: currentColor; }

The following patterns are not considered warnings:

a { border: 1px solid var(--color-white); }

a { border: 1px solid -var(--color-white); }

a { border: 1px solid color(red alpha(-10%)); }

a { color: var(--color-white); }

a { color: -var(--color-white); }

a { color: color(red alpha(-10%)); }

a { border: 1px solid @color-white; }

a { border: 1px solid -@color-white; }

a { border: 1px solid darken(#fff, 10%); }

a { color: @color-white; }

a { color: -@color-white; }

a { color: darken(#fff, 10%); }

a { border: 1px solid $color-white; }

a { border: 1px solid namespace.$color-white; }

a { border: 1px solid -$color-white; }

a { border: 1px solid darken(#fff, 10%); }

a { color: $color-white; }

a { color: namespace.$color-white; }

a { color: -$color-white; }

a { color: darken(#fff, 10%); }

recurseLonghand

If true, each longhand property will also be expanded. This is only useful for the border property.

message

You can provide your custom message string, it will interpolate the ${types}, ${value} and ${property} placeholders, like:

// .stylelintrc
"rules": {
  // ...
  "scale-unlimited/declaration-strict-value": [
    ["/color$/", "fill", "stroke"], {
      "message": "Custom expected ${types} for \"${value}\" of \"${property}\"",
    }],
  // ...
}

Autofix support

This plugin supports configurable autofixing enabled by --fix option.

Important: it's up to you to specify how autofixing should take place, this is because this plugin has to deal with dynamic values not static ones (which are predictable and very easy to autofix).

So you have to supply an autoFixFunc function and implement each fix you want by yourself. To help you with that this function receives the whole PostCSS API, all validations and configuration of this plugin, as follows node, validation, root and config. validation is a hash of { validVar, validFunc, validValue, validKeyword, longhandProp, longhandValue }, which tells you which aspect of the rule failed validation.

You may throw errors if autofixing is not possible.

Note: it's best you use a JavaScript based config file, which is easy because Stylelint utilizes cosmiconfig. Alternatively you can specify a common JS module, which will be resolved by standard require calls including support for CWD.

You can also disable autofixing by setting disableFix to true;

// .stylelintrc.js
function autoFixFunc(node, validation, root, config) {
  const { value, prop } = node

  if (prop === 'color') {
    switch (value) {
      case '#fff':
        // auto-fix by returned value
        return '$color-white'

      case 'red':
        // auto-fix by PostCSS AST tranformation
        node.value = '$color-red'
      
      default:
        // optional, you can throw your own error message if the value is not stated or handled, ex: color: blue     
        throw `Property ${prop} with value ${value} can't be autofixed!`
        // or an Error object
        throw new Error(`Property ${prop} with value ${value} can't be autofixed!`)
        // or a falsy value to use the default error message
        throw null;
    }
  }
}

module.exports = {
  "rules": {
    // ...
    "scale-unlimited/declaration-strict-value": [
      ["/color$/"], {
      autoFixFunc: autoFixFunc,
      disableFix: true | false,
    }],
    // ...
  }
}

Or:

// ./auto-fix-func.js
function autoFixFunc(node, validation, root, config) {
  const { value, prop } = node

  if (prop === 'color') {
    switch (value) {
      case '#fff':
        // auto-fix by returned value
        return '$color-white'

      case 'red':
        // auto-fix by PostCSS AST tranformation
        node.value = '$color-red'
    }
  }
}

module.exports = autoFixFunc

// .stylelintrc
"rules": {
    // ...
    "scale-unlimited/declaration-strict-value": [
      ["/color$/"], {
      autoFixFunc: './auto-fix-func.js',
      disableFix: true | false,
    }],
    // ...
  }

API

Please find the API docs at ./docs/README.md.

Credit / Inspiration

This package was mainly inspired by stylelint-declaration-use-variable. Originally I planned to contribute, but as I faced more issues I decided to write my own from scratch based on ES6.

Proudly brought to you by <scale-unlimited>

License

The MIT License (MIT)

Copyright (c) 2016 Andreas Deuschlinger

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.