Make-Cancellable-Promise

Make any Promise cancellable.

tl;dr

• Install by executing npm install make-cancellable-promise or yarn add make-cancellable-promise.
• Import by adding import makeCancellablePromise from 'make-cancellable-promise.
• Do stuff with it!

  const { promise, cancel } = makeCancellablePromise(myPromise);

User guide

makeCancellablePromise(myPromise)

A function that returns an object with two properties:

promise and cancel. promise is a wrapped around your promise. cancel is a function which stops .then() and .catch() from working on promise, even if promise passed to makeCancellablePromise resolves or rejects.

Usage

const { promise, cancel } = makeCancellablePromise(myPromise);

Typically, you'd want to use makeCancellablePromise in React components. If you call setState on an unmounted component, React will throw an error.

Here's how you can use makeCancellablePromise with React:

function MyComponent() {
  const [status, setStatus] = useState('initial');

  useEffect(() => {
    const { promise, cancel } = makeCancellable(fetchData());

    promise.then(() => setStatus('success')).catch(() => setStatus('error'));

    return () => {
      cancel();
    };
  }, []);

  const text = (() => {
    switch (status) {
      case 'pending':
        return 'Fetching…';
      case 'success':
        return 'Success';
      case 'error':
        return 'Error!';
      default:
        return 'Click to fetch';
    }
  })();

  return <p>{text}</p>;
}

License

The MIT License.

Author

Wojciech Maj