stylelint/lib/utils/isStandardSyntaxRule.js

A mighty, modern CSS linter.

/* @flow */
'use strict';

const _ = require('lodash');
const isCustomPropertySet = require('../utils/isCustomPropertySet');

/**
 * Check whether a Node is a standard rule
 */
module.exports = function(rule /*: Object*/) /*: boolean*/ {
	// Get full selector
	const selector = _.get(rule, 'raws.selector.raw', rule.selector);

	// Custom property set (e.g. --custom-property-set: {})
	if (isCustomPropertySet(rule)) {
		return false;
	}

	// Called Less mixin (e.g. a { .mixin() })
	if (rule.mixin) {
		return false;
	}

	// Less detached rulesets
	if (selector.slice(0, 1) === '@' && selector.slice(-1) === ':') {
		return false;
	}

	// Ignore Less &:extend rule
	if (rule.extend) {
		return false;
	}

	// Ignore mixin or &:extend rule
	// https://github.com/shellscape/postcss-less/blob/master/lib/less-parser.js#L52
	if (rule.params && rule.params[0]) {
		return false;
	}

	// Non-outputting Less mixin definition (e.g. .mixin() {})
	if (_.endsWith(selector, ')') && !_.includes(selector, ':')) {
		return false;
	}

	// Less guards
	if (/when\s+(not\s+)*\(/.test(selector)) {
		return false;
	}

	// Ignore Scss nested properties
	if (selector.slice(-1) === ':') {
		return false;
	}

	return true;
};