watchIgnorable

可忽略的监视

¥Ignorable watch

示例

源代码演练场

Value: 0

Log

用法

¥Usage

扩展 watch 返回额外的 ignoreUpdates(updater) 和 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.

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 时间

¥WatchOptionFlush 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' 和 '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.

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!

推荐读物

¥Recommended Readings

• 可忽略的监视 - 通过 @patak-dev

  ¥Ignorable Watch - by @patak-dev