usePrevious

保存 ref 的前一个值。

¥Holds the previous value of a ref.

用法

¥Usage

import { usePrevious } from '@vueuse/core'
import { ref } from 'vue'

const counter = ref('Hello')
const previous = usePrevious(counter)

console.log(previous.value) // undefined

counter.value = 'World'

console.log(previous.value) // Hello

类型声明

/**
 * Holds the previous value of a ref.
 *
 * @see   {@link https://vueuse.org/usePrevious}
 */
export declare function usePrevious<T>(
  value: MaybeRefOrGetter<T>,
): Readonly<Ref<T | undefined>>
export declare function usePrevious<T>(
  value: MaybeRefOrGetter<T>,
  initialValue: T,
): Readonly<Ref<T>>

源代码

源代码 • 文档

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