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.

useSubscribe

A React hook that creates a subscription to the provided observable once the component mounts and it unsubscribes when the component unmounts.

Arguments:

• source$: Source observable that the hook will subscribe to.
• unsubscribeGraceTime: Amount of time in ms that the hook should wait before unsubscribing from the source observable after it unmounts (default = 200).

Important: This hook doesn't trigger any updates.

Subscribe

A React Component that creates a subscription to the provided observable once the component mounts and it unsubscribes from it when the component unmounts.

Properties:

• source$: Source observable that the Component will subscribe to.
• graceTime: an optional property that describes the amount of time in ms that the Component should wait before unsubscribing from the source observable after it unmounts (default = 200).

Important: This Component doesn't trigger any updates.