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watchIgnorable

可忽略的监视

¥Ignorable watch

示例

Value: 0

Log

用法

¥Usage

扩展 watch 返回额外的 ignoreUpdates(updater)ignorePrevAsyncUpdates() 以忽略对源的特定更新。

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

ts
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!

冲水时间

¥Flush timing

watchIgnorable 接受与 watch 相同的选项并使用相同的默认值。因此,默认情况下,可组合项使用 flush: 'pre' 工作。

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

ignorePrevAsyncUpdates

此函数仅适用于异步刷新 'pre''post'。如果使用 flush: 'sync',则 ignorePrevAsyncUpdates() 是无操作,因为监视将在每次更新源后立即触发。它仍然提供同步刷新,因此代码可以更通用。

¥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
,
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!

¥Recommended Readings