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fromPromiseFactory

Types​

function fromPromiseFactory<GValue>(
  createPromise: IFromPromiseFactoryCreatePromiseFunction<GValue>,
  options?: IFromPromiseFactoryObservableOptions,
): IObservable<IFromPromiseFactoryObservableNotifications<GValue>>
interface IFromPromiseFactoryObservableOptions {
  signal?: AbortSignal | null;
}

interface IFromPromiseFactoryCreatePromiseFunction<GValue> {
  (signal: AbortSignal): Promise<GValue>;
}

Definition​

Creates an Observable from a Promise factory.

The promise factory is a function which receives an AbortSignal and returns a Promise.

The AbortSignal is aborted when the subscription is unsubscribed (only before the Promise is fulfilled or rejected). This signal should be used to cancel any pending work (ex: fetch, or any pending async task).

The Observable emits values in the form of Notifications:

  • next: the returned value of the promise
  • complete: when the promise is fulfilled
  • error: when the promise is rejected

You may provide a IObservableFromPromiseFactoryOptions, which may be used to force an abort from an external AbortSignal.

Diagram​

Example​

Simple http request​

const subscribe = fromPromiseFactory((signal: AbortSignal): Promise<Response> => {
  return fetch('https://some-url.site', { signal });
});

subscribe((notification) => {
  console.log(notification.name, ':', notification.value);
});

Output:

if fulfilled

next: Response
complete

if rejected

error: Error