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watchIgnorable

Category
Export Size
763 B
Last Changed
3 months ago
Alias
ignorableWatch

Ignorable watch

Demo

Value: 0

Log

Usage

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

ts
import { watchIgnorable } from '@vueuse/core'
import { nextTick, ref } from 'vue'

const source = ref('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!
import { watchIgnorable } from '@vueuse/core'
import { nextTick, ref } from 'vue'

const source = ref('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!

Flush timing

watchIgnorableaccepts 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.

ts
import { watchIgnorable } from '@vueuse/core'
import { nextTick, ref } from 'vue'

const source = ref('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!
import { watchIgnorable } from '@vueuse/core'
import { nextTick, ref } from 'vue'

const source = ref('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

Show Type Declarations
typescript
export declare type IgnoredUpdater = (updater: () => void) => void
export interface WatchIgnorableReturn {
  ignoreUpdates: IgnoredUpdater
  ignorePrevAsyncUpdates: () => void
  stop: WatchStopHandle
}
export declare function watchIgnorable<
  T extends Readonly<WatchSource<unknown>[]>,
  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
export { watchIgnorable as ignorableWatch }
export declare type IgnoredUpdater = (updater: () => void) => void
export interface WatchIgnorableReturn {
  ignoreUpdates: IgnoredUpdater
  ignorePrevAsyncUpdates: () => void
  stop: WatchStopHandle
}
export declare function watchIgnorable<
  T extends Readonly<WatchSource<unknown>[]>,
  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
export { watchIgnorable as ignorableWatch }

Source

SourceDemoDocs

Contributors

Anthony Fu
sun0day
lvjiaxuan
webfansplz

Changelog

v8.7.0 on 6/16/2022
bb0ac - fix(watch*): fix T type for WatchCallback (#1692)

Released under the MIT License.