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可忽略的监听

用法

扩展的 watch，返回额外的 ignoreUpdates(updater) 和 ignorePrevAsyncUpdates() 方法，用于忽略对源的特定更新。

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!

刷新时机

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，该组合式函数使用 flush: 'pre' 工作。

ignorePrevAsyncUpdates

此功能仅适用于异步刷新 'pre' 和 'post'。如果使用 flush: 'sync'，则 ignorePrevAsyncUpdates() 是一个空操作，因为侦听器将在源的每次更新后立即触发。它仍然为同步刷新提供，以便代码可以更通用。

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!

推荐阅读

类型声明

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<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 }