Skip to content

whenever

观察值是否为真值的简写。

¥Shorthand for watching value to be truthy.

用法

¥Usage

js
import { useAsyncState, whenever } from '@vueuse/core'

const { state, isReady } = useAsyncState(
  fetch('https://jsonplaceholder.typicode.com/todos/1').then(t => t.json()),
  {},
)

whenever(isReady, () => console.log(state))
ts
// this
whenever
(ready, () =>
console
.
log
(state))
// is equivalent to:
watch
(ready, (
isReady
) => {
if (
isReady
)
console
.
log
(state)
})

回调函数

¥Callback Function

watch 相同,回调将通过 cb(value, oldValue, onInvalidate) 调用。

¥Same as watch, the callback will be called with cb(value, oldValue, onInvalidate).

ts
whenever
(height, (
current
,
lastHeight
) => {
if (
current
>
lastHeight
)
console
.
log
(`Increasing height by ${
current
-
lastHeight
}`)
})

计算的

¥Computed

watch 相同,你可以传递一个 getter 函数来计算每次更改。

¥Same as watch, you can pass a getter function to calculate on each change.

ts
// this
whenever
(
() => counter.value === 7, () =>
console
.
log
('counter is 7 now!'),
)

选项

¥Options

选项和默认值与 watch 相同。

¥Options and defaults are same with watch.

ts
// this
whenever
(
() => counter.value === 7, () =>
console
.
log
('counter is 7 now!'),
{
flush
: 'sync' },
)

类型声明

ts
export interface WheneverOptions extends WatchOptions {
  /**
   * Only trigger once when the condition is met
   *
   * Override the `once` option in `WatchOptions`
   *
   * @default false
   */
  
once
?: boolean
} /** * Shorthand for watching value to be truthy * * @see https://vueuse.org/whenever */ export declare function
whenever
<
T
>(
source
:
WatchSource
<
T
| false | null | undefined>,
cb
:
WatchCallback
<
T
>,
options
?: WheneverOptions,
):
WatchHandle

源代码

源代码文档

变更日志

最近没有更改