Test given url availability in browser wiht fetch HTTP HEAD and specific timeout

probe.js

/**
 * Test given url availability in browser wiht fetch HTTP HEAD and specific timeout
 * @param url
 */
export function probe(url: string, opt?: RequestInit & { timeout: number }) {
  const ctrl = new AbortController();
  const timeout = (opt || {}).timeout || 5000;
  const timer = setTimeout(() => ctrl.abort(), timeout);
  return new Promise(resolve => {
    const promise = fetch(url, { signal: ctrl.signal, method: 'HEAD', ...opt })
      .then(res => resolve(res.ok))
      .catch(() => resolve(false));
    ctrl.signal.addEventListener('abort', () => {
      clearTimeout(timer);
      resolve(false);
    });
    promise.finally(() => clearTimeout(timer));
  })
}