node_modules/stylelint/lib/utils/isStandardSyntaxDeclaration.mjs

import { isRule } from './typeGuards.mjs';
import isScssVariable from './isScssVariable.mjs';

/**
 * Check whether a declaration is standard
 *
 * @param {import('postcss').Declaration | import('postcss-less').Declaration} decl
 * @returns {boolean}
 */
export default function isStandardSyntaxDeclaration(decl) {
	const prop = decl.prop;
	const parent = decl.parent;

	// SCSS var; covers map and list declarations
	if (isScssVariable(prop)) {
		return false;
	}

	// Less var (e.g. @var: x), but exclude variable interpolation (e.g. @{var})
	if (prop[0] === '@' && prop[1] !== '{') {
		return false;
	}

	// Less map declaration
	if (parent && parent.type === 'atrule' && parent.raws.afterName === ':') {
		return false;
	}

	// Less map (e.g. #my-map() { myprop: red; })
	if (
		parent &&
		isRule(parent) &&
		parent.selector &&
		parent.selector.startsWith('#') &&
		parent.selector.endsWith('()')
	) {
		return false;
	}

	// Sass nested properties (e.g. border: { style: solid; color: red; })
	if (
		parent &&
		isRule(parent) &&
		parent.selector &&
		parent.selector[parent.selector.length - 1] === ':' &&
		parent.selector.substring(0, 2) !== '--'
	) {
		return false;
	}

	// Less &:extend
	if ('extend' in decl && decl.extend) {
		return false;
	}

	return true;
}