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useObservable

Category
Package
@vueuse/rxjs
Last Changed
2 months ago

Use an Observable, return a ref and automatically unsubscribe from it when the component is unmounted. available in add-on @vueuse/rxjs

Usage

import { ref } from 'vue'
import { useObservable } from '@vueuse/rxjs'
import { interval } from 'rxjs'
import { mapTo, scan, startWith } from 'rxjs/operators'

// setup()
const count = useObservable(
  interval(1000).pipe(
    mapTo(1),
    startWith(0),
    scan((total, next) => next + total),
  ),
)
import { ref } from 'vue'
import { useObservable } from '@vueuse/rxjs'
import { interval } from 'rxjs'
import { mapTo, scan, startWith } from 'rxjs/operators'

// setup()
const count = useObservable(
  interval(1000).pipe(
    mapTo(1),
    startWith(0),
    scan((total, next) => next + total),
  ),
)

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 { ref } from 'vue'
import { useObservable } from '@vueuse/rxjs'
import { interval } from 'rxjs'
import { map } from 'rxjs/operators'

// setup()
const count = useObservable(
  interval(1000).pipe(
    map((n) => {
      if (n === 10)
        throw new Error('oops')

      return n + n
    }),
  ),
  {
    onError: (err) => {
      console.log(err.message) // "oops"
    },
  },
)
import { ref } from 'vue'
import { useObservable } from '@vueuse/rxjs'
import { interval } from 'rxjs'
import { map } from 'rxjs/operators'

// setup()
const count = useObservable(
  interval(1000).pipe(
    map((n) => {
      if (n === 10)
        throw new Error('oops')

      return n + n
    }),
  ),
  {
    onError: (err) => {
      console.log(err.message) // "oops"
    },
  },
)

Type Declarations

export interface UseObservableOptions<I> {
  onError?: (err: any) => void
  /**
   * The value that should be set if the observable has not emitted.
   */
  initialValue?: I | undefined
}
export declare function useObservable<H, I = undefined>(
  observable: Observable<H>,
  options?: UseObservableOptions<I | undefined>
): Readonly<Ref<H | I>>
export interface UseObservableOptions<I> {
  onError?: (err: any) => void
  /**
   * The value that should be set if the observable has not emitted.
   */
  initialValue?: I | undefined
}
export declare function useObservable<H, I = undefined>(
  observable: Observable<H>,
  options?: UseObservableOptions<I | undefined>
): Readonly<Ref<H | I>>

Source

SourceDocs

Contributors

Anthony Fu
Vincent Schramer
Ben Lesh
Michel Betancourt

Changelog

v8.4.0 on 5/3/2022
5f3d0 - feat(rxjs): Correct useObservable type signature and provide means of creating a non-undefined Ref (#1551)
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