EF Promise

Provides an implementation of a cancellable promise and the corresponding TypeScript interfaces

import { CancellablePromise, CancelledPromiseError} from '@ef-carbon/promise';

const promise = new CancellablePromise<number>((resolve, reject, onCancel) => {
  onCancel(() => console.log('cancelled'));

  someLongAsyncOperation().then(resolve, reject);
});

promise.cancel();  // stdout: 'cancelled'
promise.cancelled();  // -> true
promise.isCancelled();  // -> true
promise.catch(error => {
  if (error instanceof CancelledPromiseError) {
    console.log('promise was cancelled');
  }
});