fromPromise

Types

function fromPromise<GValue>(
  promise: Promise<GValue>,
): IObservable<IFromPromiseObservableNotifications<GValue>>

Definition

Creates an Observable from a Promise.

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

caution

fromPromise should be used only if you already have a Promise, else you should prefer to use fromPromiseFactory which provides an AbortSignal to properly cancel any pending tasks.

Diagram

Examples

Fulfilled Promise

const subscribe = fromPromise(Promise.resolve('Hello World !'));

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

Output:

next: Hello World !
complete

Rejected Promise

const subscribe = fromPromise(Promise.reject(new Error('Rejected')));

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

Output:

error: Error('Rejected')