1---
2category: '@RxJS'
3---
4 
5# from / fromEvent
6 
7Wrappers around RxJS's [`from()`](https://rxjs.dev/api/index/function/from) and [`fromEvent()`](https://rxjs.dev/api/index/function/fromEvent) to allow them to accept `ref`s.
8 
9## Usage
10 
11<!-- TODO: import rxjs error if enable twoslash -->
12 
13```ts no-twoslash
14import { from, fromEvent, toObserver, useSubscription } from '@vueuse/rxjs'
15import { interval } from 'rxjs'
16import { map, mapTo, takeUntil, withLatestFrom } from 'rxjs/operators'
17import { shallowRef, useTemplateRef } from 'vue'
18 
19const count = shallowRef(0)
20const button = useTemplateRef('buttonRef')
21 
22useSubscription(
23  interval(1000)
24    .pipe(
25      mapTo(1),
26      takeUntil(fromEvent(button, 'click')),
27      withLatestFrom(from(count, {
28        immediate: true,
29        deep: false,
30      })),
31      map(([curr, total]) => curr + total),
32    )
33    .subscribe(toObserver(count)), // same as ).subscribe(val => (count.value = val))
34)
35```
36 
37## from
38 
39The `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.
40 
41### Watch Options
42 
43When using `from` with a ref, you can pass Vue's `WatchOptions`:
44 
45| Option      | Type                        | Description                        |
46| ----------- | --------------------------- | ---------------------------------- |
47| `immediate` | `boolean`                   | Emit the current value immediately |
48| `deep`      | `boolean`                   | Deeply watch nested objects        |
49| `flush`     | `'pre' \| 'post' \| 'sync'` | Timing of the callback flush       |
50 
51## fromEvent
52 
53The `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.
54 
55```ts no-twoslash
56import { fromEvent, useSubscription } from '@vueuse/rxjs'
57import { useTemplateRef } from 'vue'
58 
59const button = useTemplateRef('buttonRef')
60 
61// Will automatically subscribe when the button element becomes available
62useSubscription(
63  fromEvent(button, 'click').subscribe(() => {
64    console.log('clicked!')
65  })
66)
67```
68 
69## Type Declarations
70 
71```ts
72export declare function from<T>(
73  value: ObservableInput<T> | Ref<T>,
74  watchOptions?: WatchOptions,
75): Observable<T>
76export declare function fromEvent<T extends HTMLElement | null>(
77  value: MaybeRef<T>,
78  event: string,
79): Observable<Event>
80```
81