.stylelintrc.js

module.exports = {
    // documentation about rules can be found on https://stylelint.io/user-guide/rules/
    // based on https://github.com/stylelint/stylelint-config-standard/blob/master/index.js
    // configurator avaialble https://maximgatilin.github.io/stylelint-config/
    'rules': {
        'at-rule-empty-line-before': [ 'always', {
            except: [
                'blockless-after-same-name-blockless',
                'first-nested',
            ],
            ignore: ['after-comment', 'inside-block'],
        } ],
        'at-rule-name-case': 'lower',
        'at-rule-name-space-after': 'always-single-line',
        'at-rule-semicolon-newline-after': 'always',
        'block-closing-brace-empty-line-before': 'never',
        'block-closing-brace-newline-after': 'always',
        'block-closing-brace-newline-before': 'always-multi-line',
        'block-closing-brace-space-before': 'always-single-line',
        'block-no-empty': true,
        'block-opening-brace-newline-after': 'always-multi-line',
        'block-opening-brace-space-after': 'always-single-line',
        'block-opening-brace-space-before': 'always',
        'color-hex-case': 'lower',
        'color-hex-length': 'short',
        'color-no-invalid-hex': true,
        // 'comment-empty-line-before': ['never'],
        'comment-no-empty': true,
        'comment-whitespace-inside': 'always',
        'custom-property-empty-line-before': [ 'always', {
            except: [
                'after-custom-property',
                'first-nested',
            ],
            ignore: [
                'after-comment',
                'inside-single-line-block',
            ],
        } ],
        'declaration-bang-space-after': 'never',
        'declaration-bang-space-before': 'always',
        'declaration-block-no-duplicate-properties': [ true, {
            ignore: ['consecutive-duplicates-with-different-values'],
        } ],
        'declaration-block-no-redundant-longhand-properties': true,
        'declaration-block-no-shorthand-property-overrides': true,
        'declaration-block-semicolon-newline-after': 'always-multi-line',
        'declaration-block-semicolon-space-after': 'always-single-line',
        'declaration-block-semicolon-space-before': 'never',
        'declaration-block-single-line-max-declarations': 1,
        'declaration-block-trailing-semicolon': 'always',
        'declaration-colon-newline-after': 'always-multi-line',
        'declaration-colon-space-after': 'always-single-line',
        'declaration-colon-space-before': 'never',
        'declaration-empty-line-before': [ 'always', {
            except: [
                'after-declaration',
                'first-nested',
            ],
            ignore: [
                'after-comment',
                'inside-single-line-block',
            ],
        } ],
        'font-family-no-duplicate-names': true,
        'function-calc-no-unspaced-operator': true,
        'function-comma-newline-after': 'always-multi-line',
        'function-comma-space-after': 'always-single-line',
        'function-comma-space-before': 'never',
        'function-linear-gradient-no-nonstandard-direction': true,
        'function-max-empty-lines': 0,
        'function-name-case': 'lower',
        'function-parentheses-newline-inside': 'always-multi-line',
        'function-parentheses-space-inside': 'never-single-line',
        'function-whitespace-after': 'always',
        'indentation': 4,
        'keyframe-declaration-no-important': true,
        'length-zero-no-unit': true,
        'max-empty-lines': 1,
        'media-feature-colon-space-after': 'always',
        'media-feature-colon-space-before': 'never',
        'media-feature-name-case': 'lower',
        'media-feature-name-no-unknown': true,
        'media-feature-parentheses-space-inside': 'never',
        'media-feature-range-operator-space-after': 'always',
        'media-feature-range-operator-space-before': 'always',
        'media-query-list-comma-newline-after': 'always-multi-line',
        'media-query-list-comma-space-after': 'always-single-line',
        'media-query-list-comma-space-before': 'never',
        'no-empty-source': true,
        'no-eol-whitespace': true,
        'no-extra-semicolons': true,
        'no-invalid-double-slash-comments': true,
        'no-missing-end-of-source-newline': true,
        'number-leading-zero': 'always',
        'number-no-trailing-zeros': true,
        'property-case': 'lower',
        'property-no-unknown': true,
        'rule-empty-line-before': [ 'always-multi-line', {
            except: ['first-nested'],
            ignore: ['after-comment'],
        } ],
        'selector-attribute-brackets-space-inside': 'never',
        'selector-attribute-operator-space-after': 'never',
        'selector-attribute-operator-space-before': 'never',
        'selector-combinator-space-after': 'always',
        'selector-combinator-space-before': 'always',
        'selector-descendant-combinator-no-non-space': true,
        'selector-list-comma-newline-after': 'always',
        'selector-list-comma-space-before': 'never',
        'selector-max-empty-lines': 0,
        'selector-pseudo-class-case': 'lower',
        'selector-pseudo-class-no-unknown': true,
        'selector-pseudo-class-parentheses-space-inside': 'never',
        'selector-pseudo-element-case': 'lower',
        'selector-pseudo-element-colon-notation': 'single',
        'selector-pseudo-element-no-unknown': true,
        // 'selector-no-type': true,
        'selector-no-vendor-prefix': true,
        // 'selector-no-universal': true,
        'selector-type-case': 'lower',
        'selector-type-no-unknown': true,
        'shorthand-property-no-redundant-values': true,
        'string-no-newline': true,
        'unit-case': 'lower',
        'unit-no-unknown': true,
        'value-list-comma-newline-after': 'always-multi-line',
        'value-list-comma-space-after': 'always-single-line',
        'value-list-comma-space-before': 'never',
        'value-list-max-empty-lines': 0,
    },
};