javascript: wait until a condition becomes true

waitUntil.ts

export function waitUntil<T>(condition: () => T, timeout = 10000, interval = 50): Promise<T> {
  let result = condition();
  if (result) return Promise.resolve(result);
  return new Promise((resolve) => {
    const finish = () => {
      clearInterval(intervalId);
      resolve(result);
    };
    const intervalId = setInterval(() => {
      result = condition();
      if (result) finish();
    }, interval);
    setTimeout(finish, timeout);
  });
}