asyncファンクションで例外が発生したら指定回数リトライする関数

example.js

retry(async (abort, num) => {
  const res = fetch('https://xxxx').then(res => res.json());
  if (condition) {
    // 特定の条件の場合にリトライをしないで処理を抜ける場合はabortをコールする
    abort(new Error('error message'));
  }
}, {retryMax: 3, sleep: 300});

retry.js

export const retry = (fn, option = {retryMax: 2, sleep: null}) => {
  let retryCount = 0;
  let aborted = false;

  const run = (resolve, reject) => {
    const abort = err => {
      aborted = true;
      reject(err || new Error('Aborted.'));
    };

    const onError = err => {
      if (!aborted) {
        if (retryCount < option.retryMax) {
          retryCount++;
          runAttempt();
          return;
        } else {
          reject(err);
        }
      }
    };

    const runAttempt = async () => {
      if (retryCount > 0 && option.sleep) {
        await sleep();
      }

      fn(abort, retryCount)
        .then(resolve)
        .catch(onError);
    };

    runAttempt();
  };

  const sleep = () => {
    return new Promise((resolve, reject) => {
      console.log(`retry sleep ${option.sleep}`);
      setTimeout(() => resolve(), option.sleep);
    });
  };

  return new Promise(run);
};