MediaQuery Class — svelte Architecture

Source Code

packages/svelte/src/reactivity/media-query.js lines 37–55

export class MediaQuery extends ReactiveValue {
	/**
	 * @param {string} query A media query string
	 * @param {boolean} [fallback] Fallback value for the server
	 */
	constructor(query, fallback) {
		let final_query =
			parenthesis_regex.test(query) ||
			// we need to use `some` here because technically this `window.matchMedia('random,screen')` still returns true
			query.split(/[\s,]+/).some((keyword) => non_parenthesized_keywords.has(keyword.trim()))
				? query
				: `(${query})`;
		const q = window.matchMedia(final_query);
		super(
			() => q.matches,
			(update) => on(q, 'change', update)
		);
	}
}