1---
2category: Watch
3---
4 
5# watchOnce
6 
7Shorthand for watching value with `{ once: true }`. Once the callback fires once, the watcher will be stopped.
8See [Vue's docs](https://vuejs.org/guide/essentials/watchers.html#once-watchers) for full details.
9 
10## Usage
11 
12Similar to `watch`, but with `{ once: true }`
13 
14```ts
15import { watchOnce } from '@vueuse/core'
16 
17watchOnce(source, () => {
18  // triggers only once
19  console.log('source changed!')
20})
21```
22 
23## Type Declarations
24 
25```ts
26export declare function watchOnce<T extends Readonly<MultiWatchSources>>(
27  source: [...T],
28  cb: WatchCallback<MapSources<T>, MapOldSources<T, true>>,
29  options?: Omit<WatchOptions<true>, "once">,
30): WatchHandle
31export declare function watchOnce<T>(
32  source: WatchSource<T>,
33  cb: WatchCallback<T, T | undefined>,
34  options?: Omit<WatchOptions<true>, "once">,
35): WatchHandle
36export declare function watchOnce<T extends object>(
37  source: T,
38  cb: WatchCallback<T, T | undefined>,
39  options?: Omit<WatchOptions<true>, "once">,
40): WatchHandle
41```
42