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category, alias
category alias
Watch ignorableWatch

watchIgnorable

Ignorable watch

Usage

Extended watch that returns extra ignoreUpdates(updater) and ignorePrevAsyncUpdates() to ignore particular updates to the source.

import { watchIgnorable } from '@vueuse/core';
import { nextTick, shallowRef } from 'vue';

const source = shallowRef('foo');

const { stop, ignoreUpdates } = watchIgnorable(source, (v) => console.log(`Changed to ${v}!`));

source.value = 'bar';
await nextTick(); // logs: Changed to bar!

ignoreUpdates(() => {
  source.value = 'foobar';
});
await nextTick(); // (nothing happened)

source.value = 'hello';
await nextTick(); // logs: Changed to hello!

ignoreUpdates(() => {
  source.value = 'ignored';
});
source.value = 'logged';

await nextTick(); // logs: Changed to logged!

WatchOptionFlush timing

watchIgnorable accepts the same options as watch and uses the same defaults. So, by default the composable works using flush: 'pre'.

ignorePrevAsyncUpdates

This feature is only for async flush 'pre' and 'post'. If flush: 'sync' is used, ignorePrevAsyncUpdates() is a no-op as the watch will trigger immediately after each update to the source. It is still provided for sync flush so the code can be more generic.

import { watchIgnorable } from '@vueuse/core';
import { nextTick, shallowRef } from 'vue';

const source = shallowRef('foo');

const { ignorePrevAsyncUpdates } = watchIgnorable(source, (v) => console.log(`Changed to ${v}!`));

source.value = 'bar';
await nextTick(); // logs: Changed to bar!

source.value = 'good';
source.value = 'by';
ignorePrevAsyncUpdates();

await nextTick(); // (nothing happened)

source.value = 'prev';
ignorePrevAsyncUpdates();
source.value = 'after';

await nextTick(); // logs: Changed to after!

Type Declarations

export type IgnoredUpdater = (updater: () => void) => void;
export type IgnoredPrevAsyncUpdates = () => void;
export interface WatchIgnorableReturn {
  ignoreUpdates: IgnoredUpdater;
  ignorePrevAsyncUpdates: IgnoredPrevAsyncUpdates;
  stop: WatchStopHandle;
}
export declare function watchIgnorable<
  T extends Readonly<MultiWatchSources>,
  Immediate extends Readonly<boolean> = false,
>(
  sources: [...T],
  cb: WatchCallback<MapSources<T>, MapOldSources<T, Immediate>>,
  options?: WatchWithFilterOptions<Immediate>,
): WatchIgnorableReturn;
export declare function watchIgnorable<T, Immediate extends Readonly<boolean> = false>(
  source: WatchSource<T>,
  cb: WatchCallback<T, Immediate extends true ? T | undefined : T>,
  options?: WatchWithFilterOptions<Immediate>,
): WatchIgnorableReturn;
export declare function watchIgnorable<
  T extends object,
  Immediate extends Readonly<boolean> = false,
>(
  source: T,
  cb: WatchCallback<T, Immediate extends true ? T | undefined : T>,
  options?: WatchWithFilterOptions<Immediate>,
): WatchIgnorableReturn;
/** @deprecated use `watchIgnorable` instead */
export declare const ignorableWatch: typeof watchIgnorable;