useWatchExtractedObservable

Category

@RxJS

Export Size

414 B

Package

@reause/rxjs

Last Changed

5 days ago

Watch the values of an RxJS Observable as extracted from one or more hooks.

Automatically unsubscribe on observable change, and automatically unsubscribe from it when the component is unmounted.

Demo

Usage

import type { Observable } from 'rxjs'
import { useWatchExtractedObservable } from '@reause/rxjs'
import { useState } from 'react'
import { Subject } from 'rxjs'

interface Player {
  progress$: Observable<number>
}

export function PlayerProgress() {
  const [player] = useState<Player>(() => ({ progress$: new Subject<number>() }))
  const [progress, setProgress] = useState(0)

  const { stop } = useWatchExtractedObservable(player, p => p.progress$, setProgress)

  return (
    <div>
      <p>{progress}</p>
      <button onClick={() => stop()}>Stop watching</button>
    </div>
  )
}

If you want to add custom error handling to an Observable that might error, you can supply an optional onError configuration. Without this, RxJS will treat any error in the supplied Observable as an "unhandled error" and it will be thrown in a new call stack and reported to window.onerror (or process.on('error') if you happen to be in Node).

You can also supply an optional onComplete configuration if you need to attach special behavior when the watched observable completes.

useWatchExtractedObservable(player, p => p.progress$, setProgress, {
  onError: (err: unknown) => {
    console.error(err)
  },
  onComplete: () => {
    setProgress(100) // or 0, or whatever
  },
})

Subscription Options

Option	Type	Description
onError	(err: unknown) => void	Error handler for Observable errors
onComplete	() => void	Called when the Observable completes

Return Value

Returns a WatchHandle that can be used to stop watching:

const { stop } = useWatchExtractedObservable(player, p => p.progress$, setProgress)

// Later, stop watching
stop()

Type Declarations

export type OnCleanup = (cleanupFn: () => void) => void

export type WatchExtractedObservableExtractor<Value, E> = (value: NonNullable<Value>, onCleanup: OnCleanup) => Observable<E>

export interface UseWatchExtractedObservableOptions {
    deps?: unknown[];
    onError?: (err: unknown) => void;
    onComplete?: () => void;
}

export interface UseWatchExtractedObservableReturn {
    stop: () => void;
}

export function useWatchExtractedObservable<Value, E>(value: Value | null | undefined, extractor: WatchExtractedObservableExtractor<Value, E>, callback: (snapshot: E) => void, options?: UseWatchExtractedObservableOptions): UseWatchExtractedObservableReturn

Source

Source · Demo · VueUse

Contributors

Changelog

v0.1.0 on

de6df - fix(rxjs): resolve useWatchExtractedObservable audit findings (#813)

6a703 - feat(rxjs): add useWatchExtractedObservable (#262)