abort-controller-x/src/delay.ts

Abortable async function helpers

import {execute} from './execute';

/**
 * Returns a promise that fulfills after delay and rejects with
 * `AbortError` once `signal` is aborted.
 *
 * The delay time is specified as a `Date` object or as an integer denoting
 * milliseconds to wait.
 * 
 * Example:
 * 
 *     // Make requests repeatedly with a delay between consecutive requests
 *     while (true) {
 *       await makeRequest(signal, params);
 *       await delay(signal, 1000);
 *     }
 * 
 * Example:
 * 
 *     // Make requests repeatedly with a fixed interval
 *     import {addMilliseconds} from 'date-fns';
 * 
 *     let date = new Date();
 * 
 *     while (true) {
 *       await makeRequest(signal, params);
 *       
 *       date = addMilliseconds(date, 1000);
 *       await delay(signal, date);
 *     }
 */
export function delay(
  signal: AbortSignal,
  dueTime: number | Date,
): Promise<void> {
  return execute<void>(signal, resolve => {
    const ms =
      typeof dueTime === 'number' ? dueTime : dueTime.getTime() - Date.now();

    const timer = setTimeout(resolve, ms);

    return () => {
      clearTimeout(timer);
    };
  });
}