usePrevious
保存 ref 的先前值。
用法
ts
import { usePrevious } from '@vueuse/core'
import { shallowRef } from 'vue'
const counter = shallowRef('Hello')
const previous = usePrevious(counter)
console.log(previous.value) // undefined
counter.value = 'World'
console.log(previous.value) // Hello
类型声明
typescript
/**
* Holds the previous value of a ref.
*
* @see {@link https://vueuse.org.cn/usePrevious}
*/
export declare function usePrevious<T>(
value: MaybeRefOrGetter<T>,
): Readonly<ShallowRef<T | undefined>>
export declare function usePrevious<T>(
value: MaybeRefOrGetter<T>,
initialValue: T,
): Readonly<ShallowRef<T>>
源码
贡献者
更新日志
v12.8.0
于 2025/3/5v12.0.0-beta.1
于 2024/11/21v10.0.0-beta.4
于 2023/4/134d757
- feat(types)!: 将 MaybeComputedRef
重命名为 MaybeRefOrGetter
10e98
- feat(toRef)!: 将 resolveRef
重命名为 toRef
v9.12.0
于 2023/1/29e101f
- feat: 新函数