useExtractedObservable

Category

@RxJS

Export Size

344 B

Package

@vueuse/rxjs

Last Changed

2 months ago

Use an RxJS Observable as extracted from one or more composables, return a ref, and automatically unsubscribe from it when the component is unmounted.

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

Supports signatures that match all overloads of watch. Available in the @vueuse/rxjs add-on.

Usage

TypeScript

import { useExtractedObservable } from '@vueuse/rxjs'
import ObservableSocket from 'observable-socket'
import { computed } from 'vue'
import { makeSocket, useUser } from '../some/lib/func'

// setup()
const user = useUser()
const lastMessage = useExtractedObservable(user, u => ObservableSocket.create(makeSocket(u.id)).down)

import { useExtractedObservable } from '@vueuse/rxjs'
import ObservableSocket from 'observable-socket'
import { makeSocket, useUser } from '../some/lib/func'
// setup()
const user = useUser()
const lastMessage = useExtractedObservable(
  user,
  (u) => ObservableSocket.create(makeSocket(u.id)).down,
)

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).

import { useExtractedObservable } from '@vueuse/rxjs'
import { interval } from 'rxjs'
import { mapTo, scan, startWith, tap } from 'rxjs/operators'
import { shallowRef } from 'vue'

// setup()
const start = shallowRef(0)

const count = useExtractedObservable(
  start,
  (start) => {
    return interval(1000).pipe(
      mapTo(1),
      startWith(start),
      scan((total, next) => next + total),
      tap((n) => {
        if (n === 10)
          throw new Error('oops')
      })
    )
  },
  {
    onError: (err) => {
      console.log(err.message) // "oops"
    },
  }
)

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

import { useExtractedObservable } from '@vueuse/rxjs'
import { interval } from 'rxjs'
import { mapTo, scan, startWith, takeWhile } from 'rxjs/operators'
import { shallowRef } from 'vue'

// setup()
const start = shallowRef(0)

const count = useExtractedObservable(
  start,
  (start) => {
    return interval(1000).pipe(
      mapTo(1),
      startWith(start),
      scan((total, next) => next + total),
      takeWhile(num => num < 10)
    )
  },
  {
    onComplete: () => {
      console.log('Done!')
    },
  }
)

If you want, you can also pass watch options as the last argument:

TypeScript

import { useExtractedObservable } from '@vueuse/rxjs'
import { interval } from 'rxjs'
import { mapTo, scan, startWith, takeWhile } from 'rxjs/operators'
import { shallowRef } from 'vue'

// setup()
const start = shallowRef<number>()

const count = useExtractedObservable(
  start,
  (start) => {
    return interval(1000).pipe(
      mapTo(1),
      startWith(start),
      scan((total, next) => next + total),
      takeWhile(num => num < 10)
    )
  },
  {},
  {
    immediate: false
  }
)

import { useExtractedObservable } from '@vueuse/rxjs'
import { interval } from 'rxjs'
import { mapTo, scan, startWith, takeWhile } from 'rxjs/operators'
import { shallowRef } from 'vue'
// setup()
const start = shallowRef()
const count = useExtractedObservable(
  start,
  (start) => {
    return interval(1000).pipe(
      mapTo(1),
      startWith(start),
      scan((total, next) => next + total),
      takeWhile((num) => num < 10),
    )
  },
  {},
  {
    immediate: false,
  },
)

Type Declarations

Show Type Declarations

export interface UseExtractedObservableOptions<E>
  extends UseObservableOptions<E> {
  onComplete?: () => void
}
export declare function useExtractedObservable<
  T extends MultiWatchSources,
  E,
  Immediate extends Readonly<boolean> = false,
>(
  sources: [...T],
  extractor: WatchExtractedObservableCallback<
    MapSources<T>,
    MapOldSources<T, Immediate>,
    E
  >,
  options?: UseExtractedObservableOptions<E>,
  watchOptions?: WatchOptions<Immediate>,
): Readonly<ShallowRef<E>>
export declare function useExtractedObservable<
  T extends Readonly<MultiWatchSources>,
  E,
  Immediate extends Readonly<boolean> = false,
>(
  sources: T,
  extractor: WatchExtractedObservableCallback<
    MapSources<T>,
    MapOldSources<T, Immediate>,
    E
  >,
  options?: UseExtractedObservableOptions<E>,
  watchOptions?: WatchOptions<Immediate>,
): Readonly<ShallowRef<E>>
export declare function useExtractedObservable<
  T,
  E,
  Immediate extends Readonly<boolean> = false,
>(
  sources: WatchSource<T>,
  extractor: WatchExtractedObservableCallback<
    T,
    Immediate extends true ? T | undefined : T,
    E
  >,
  options?: UseExtractedObservableOptions<E>,
  watchOptions?: WatchOptions<Immediate>,
): Readonly<ShallowRef<E>>
export declare function useExtractedObservable<
  T extends object,
  E,
  Immediate extends Readonly<boolean> = false,
>(
  sources: T,
  extractor: WatchExtractedObservableCallback<
    T,
    Immediate extends true ? T | undefined : T,
    E
  >,
  options?: UseExtractedObservableOptions<E>,
  watchOptions?: WatchOptions<Immediate>,
): Readonly<ShallowRef<E>>

Source

Source • Docs

Contributors

Anthony Fu

IlyaL

Anthony Fu

Arthur Darkstone

SerKo

Robin

OrbisK

Voltra

Changelog

v14.0.0-alpha.0 on 9/1/2025

00a72 - fix(types): update type casting for watch functions to use WatchSource (#4966)

v12.0.0-beta.1 on 11/21/2024

0a9ed - feat!: drop Vue 2 support, optimize bundles and clean up (#4349)

v10.5.0 on 10/7/2023

23b8c - feat(rxjs): add useExtractedObservable and watchExtractedObservable (#3453)