discordeno/tests/util/delay_until.ts

export async function delayUntil(maxMs: number, isReady: () => boolean, timeoutTime= 100): Promise<void> {
  const maxTime = Date.now() + maxMs;

  function hackyFix(resolve: () => void) {
    if (isReady() || Date.now() >= maxTime) {
      resolve();
    }
    else {
      setTimeout(async () => {
        await hackyFix(resolve);
        resolve();
      }, timeoutTime);
    }
  }

  return new Promise(resolve => hackyFix(resolve));
}