Asynchronous retry pattern with delay in Typescript

README.md

Retrying an asynchronous function a number of times

Flems Playground

test.ts

/** Dummy worker */
const worker = async () => {
  return new Promise((resolve, reject) => {
    if (Math.random() < 0.1) resolve(true);
    else reject('I failed');
  })
};

/** Main loop */
for (let i = 0; i<10; i++) {
  const result = await retry(worker).catch(e => console.log(e));
  result && console.log(result);  
}

utils.ts

/** Wait or sleep a number of milliseconds */
const wait = (msecDuration: number): Promise<void> => {
  return new Promise((resolve) => setTimeout(resolve, msecDuration));
};

/** Retry an asynchronous function a number of times, waiting in between */
export const retry = async <T>(
  workerFn: { (): Promise<T>; },
  retries = 3,
  delay = 500
): Promise<T> => {
  try {
    return await workerFn();
  } catch (e) {
    if (retries > 1) {
      await wait(delay);
      return await retry(workerFn, retries - 1, delay * 2);
    } else {
      throw e;
    }
  }
};