Promise Timeout

promise-timeout.js

/**
 * @param {Promise<T>} p
 * @param {int} duration Milliseconds until timeout
 * 
 * @returns {Promise<T, TimeoutError>}
 */
function timeout(p, duration) {
  const failAfterDuration = new Promise((resolve, reject) => {
    const err = Object.assign(new Error(`Timed out after ${duration}ms`), { name: 'TimeoutError' });
    
    setTimeout(() => reject(err), duration);
  });
  
  return Promise.race([p, failAfterDuration]);
}