cancelable-promise.js

const delay = (delay, value) => {
  let timeout;
  let _reject = null;
  const promise = new Promise((resolve, reject) => {
    _reject= reject;
    timeout = setTimeout(resolve, delay, value);
  });
  return {
    promise,
    cancel() {
      if(timeout) {
        clearTimeout(timeout);
        timeoout = null;
        _reject();
        _reject = null;
      }
    }
  };
};

/* usage

  const delayed = delay(5000, value);
  delayed.promise.then((value) => console.log(value)).catch(() => console.error("Rejected"));
  delayed.cancel();

*/