stylelint-use-nesting/lib/are-rules-potential-nesting-at-rule.mjs

Enforce nesting when it is possible in CSS

export default function areRulesPotentialNestingAtRule(rule1, rule2, opts) {
	const except = [].concat(Object(opts).except || []);
	const only = [].concat(Object(opts).only || []);

	return rule1.selectors && rule2.selectors && rule2.selectors.every(
		rule2Selector => rule1.selectors.every(
			rule1Selector =>
				rule2Selector.length < rule1Selector.length &&
				` ${rule2Selector}` === rule1Selector.slice(-rule2Selector.length - 1) &&
				(!except.length || except.some(
					entry => entry instanceof RegExp
						? !entry.test(rule1Selector.slice(0, -rule2Selector.length - 1))
					: entry !== rule1Selector.slice(0, -rule2Selector.length - 1)
				)) &&
				(!only.length || only.some(
					entry => entry instanceof RegExp
						? entry.test(rule1Selector.slice(0, -rule2Selector.length - 1))
					: entry === rule1Selector.slice(0, -rule2Selector.length - 1)
				))
		)
	);
}