whenever

观察值是否为真值的简写。

¥Shorthand for watching value to be truthy.

用法

¥Usage

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))

// this
whenever(ready, () => console.log(state))

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

回调函数

¥Callback Function

与 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).

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

计算的

¥Computed

与 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.

// 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.

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