packages/shared/watchIgnorable/index.md
Ignorable watch
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!
watchIgnorable accepts the same options as watch and uses the same defaults.
So, by default the composable works using flush: 'pre'.
ignorePrevAsyncUpdatesThis 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!