fuel-price/.agents/skills/vueuse-functions/references/from.md

category

category
@RxJS

from / fromEvent

Wrappers around RxJS's from() and fromEvent() to allow them to accept refs.

Usage

import { from, fromEvent, toObserver, useSubscription } from '@vueuse/rxjs'
import { interval } from 'rxjs'
import { map, mapTo, takeUntil, withLatestFrom } from 'rxjs/operators'
import { shallowRef, useTemplateRef } from 'vue'

const count = shallowRef(0)
const button = useTemplateRef('buttonRef')

useSubscription(
  interval(1000)
    .pipe(
      mapTo(1),
      takeUntil(fromEvent(button, 'click')),
      withLatestFrom(from(count, {
        immediate: true,
        deep: false,
      })),
      map(([curr, total]) => curr + total),
    )
    .subscribe(toObserver(count)), // same as ).subscribe(val => (count.value = val))
)

from

The from function can accept either a standard RxJS ObservableInput or a Vue ref. When passed a ref, it creates an Observable that emits whenever the ref's value changes.

Watch Options

When using from with a ref, you can pass Vue's WatchOptions:

Option	Type	Description
immediate	boolean	Emit the current value immediately
deep	boolean	Deeply watch nested objects
flush	'pre' | 'post' | 'sync'	Timing of the callback flush

fromEvent

The fromEvent function extends RxJS's fromEvent to accept a ref to an element. When the ref's value changes (e.g., after the component mounts), it automatically subscribes to the new element.

import { fromEvent, useSubscription } from '@vueuse/rxjs'
import { useTemplateRef } from 'vue'

const button = useTemplateRef('buttonRef')

// Will automatically subscribe when the button element becomes available
useSubscription(
  fromEvent(button, 'click').subscribe(() => {
    console.log('clicked!')
  })
)

Type Declarations

export declare function from<T>(
  value: ObservableInput<T> | Ref<T>,
  watchOptions?: WatchOptions,
): Observable<T>
export declare function fromEvent<T extends HTMLElement | null>(
  value: MaybeRef<T>,
  event: string,
): Observable<Event>