Retry function and wait until success

index.js

/**
 * This example shows how we can can preform some check multiple times, and if it
 * fails we wait a predetermined amount of time and try again. Only returning
 * once there is a successful attempt.
 *
 * This can be useful such as preforming a startup check if you have a Database
 * Also starting up at the same time, and want rather simple logic to wait on
 * the database fully starting up.
 *
 * This example purposefully fails until ten attempts have been made, at which
 * point it will succeed.
 */

const DELAY_TIME_MS = 1000;
const RETRY_AMOUNT = 10;

(async () => {

  await waitRetry();

  console.log("We are done waiting...");

})();

async function waitRetry() {
  const delay = (ms) => {
    return new Promise(resolve => setTimeout(resolve, ms));
  };

  const retry = async (fn, retries, delayMs) => {
    let attempt = 0;

    while(true) {
      try {
        console.log(`Running Attempt ${attempt+1}/${retries}...`);
        return await fn();
      } catch(err) {
        console.log(`Attempt ${attempt+1}/${retries} failed. Retrying in ${delayMs}...`);

        if (attempt++ < retries) {
          await delay(delayMs);
        } else {
          console.error(err);
          process.exit(1);
        }
      }
    }
  };

  return retry(async () => {
    await attemptToRun();
  }, RETRY_AMOUNT, DELAY_TIME_MS);
}

let retryCount = 0;

async function attemptToRun() {
  retryCount = retryCount + 1;

  return new Promise((resolve, reject) => {
    setTimeout(() => {
      if (retryCount === 10) {
        resolve("resolved");
      } else {
        reject("Failed");
      }
    }, 2000);
  });
}