react-rxjs/packages/core

@react-rxjs/core

Installation

npm install @react-rxjs/core

API

bind

Observable overload

const [useCounter, sharedCounter$] = bind(
  clicks$.pipe(
    scan((prev) => prev + 1, 0),
    startWith(0),
  ),
)

Accepts: An Observable.

Returns [1, 2]

1. A React Hook that yields the latest emitted value of the observable. If the Observable doesn't synchronously emit a value upon the first subscription, then the hook will leverage React Suspense while it's waiting for the first value.

2. A sharedLatest version of the observable. It can be used for composing other streams that depend on it. The shared subscription is closed as soon as there are no subscribers to that observable.

Factory Observables overload

const [useStory, getStory$] = bind((storyId: number) =>
  getStoryWithUpdates$(storyId),
)

const Story: React.FC<{ id: number }> = ({ id }) => {
  const story = useStory(id)

  return (
    <article>
      <h1>{story.title}</h1>
      <p>{story.description}</p>
    </article>
  )
}

Accepts: A factory function that returns an Observable.

Returns [1, 2]

1. A React Hook function with the same parameters as the factory function. This hook will yield the latest update from the observable returned from the factory function. If the Observable doesn't synchronously emit a value upon the first subscription, then the hook will leverage React Suspense while it's waiting for the first value.

2. A sharedLatest version of the observable returned by the factory function. It can be used for composing other streams that depend on it. The shared subscription is closed as soon as there are no subscribers to that observable.

shareLatest

const activePlanetName$ = planet$.pipe(
  filter((planet) => planet.isActive),
  map((planet) => planet.name),
  shareLatest(),
)

A RxJS pipeable operator which shares and replays the latest emitted value. It's the equivalent of:

const shareLatest = <T>(): Observable<T> =>
  source$.pipe(
    multicast(() => new ReplaySubject<T>(1)),
    refCount(),
  )

The enhanced observables returned from bind have been enhanced with this operator.

SUSPENSE

const story$ = selectedStoryId$.pipe(
  switchMap((id) => concat(SUSPENSE, getStory$(id))),
)

This is a special symbol that can be emitted from our observables to let the react hook know that there is a value on its way, and that we want to leverage React Suspense while we are waiting for that value.

suspend

const story$ = selectedStoryId$.pipe(
  switchMap(id => suspend(getStory$(id))
)

A RxJS creation operator that prepends a SUSPENSE on the source observable.

suspended

const story$ = selectedStoryId$.pipe(
  switchMap((id) => getStory$(id).pipe(suspended())),
)

The pipeable version of suspend

switchMapSuspended

const story$ = selectedStoryId$.pipe(switchMapSuspended(getStory$))

Like switchMap but applying a startWith(SUSPENSE) to the inner observable.