useMemoize

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最后更改

4 个月前

缓存函数的根据参数的结果，并保持其响应性。它也可以用于异步函数，并将重用现有的 Promise 以避免同时获取相同的数据。

提示

结果不会自动清除。如果您不再需要这些结果，或者使用自己的缓存机制以避免内存泄漏，请调用 clear()。

用法

TypeScript

import { useMemoize } from '@vueuse/core'

const getUser = useMemoize(
  async (userId: number): Promise<UserData> =>
    axios.get(`users/${userId}`).then(({ data }) => data),
)

const user1 = await getUser(1) // Request users/1
const user2 = await getUser(2) // Request users/2
// ...
const user1 = await getUser(1) // Retrieve from cache

// ...
const user1 = await getUser.load(1) // Request users/1

// ...
getUser.delete(1) // Delete cache from user 1
getUser.clear() // Clear full cache

import { useMemoize } from '@vueuse/core'
const getUser = useMemoize(async (userId) =>
  axios.get(`users/${userId}`).then(({ data }) => data),
)
const user1 = await getUser(1) // Request users/1
const user2 = await getUser(2) // Request users/2
// ...
const user1 = await getUser(1) // Retrieve from cache
// ...
const user1 = await getUser.load(1) // Request users/1
// ...
getUser.delete(1) // Delete cache from user 1
getUser.clear() // Clear full cache

与 computed 或 asyncComputed 结合使用以实现响应性

const user1 = asyncComputed(() => getUser(1))
// ...
await getUser.load(1) // Will also update user1

解析缓存键

缓存的键由传递给函数的参数确定，默认情况下将使用 JSON.stringify 进行序列化。这将允许相等的对象接收相同的缓存键。如果您想自定义键，可以传递 getKey

TypeScript

const getUser = useMemoize(
  async (userId: number, headers: AxiosRequestHeaders): Promise<UserData> =>
    axios.get(`users/${userId}`, { headers }).then(({ data }) => data),
  {
    // Use only userId to get/set cache and ignore headers
    getKey: (userId, headers) => userId,
  },
)

const getUser = useMemoize(
  async (userId, headers) =>
    axios.get(`users/${userId}`, { headers }).then(({ data }) => data),
  {
    // Use only userId to get/set cache and ignore headers
    getKey: (userId, headers) => userId,
  },
)

自定义缓存机制

默认情况下，结果缓存在 Map 中。您可以通过传递 cache 作为具有以下结构的选项来实现您自己的机制

TypeScript

export interface MemoizeCache<Key, Value> {
  /**
   * Get value for key
   */
  get: (key: Key) => Value | undefined
  /**
   * Set value for key
   */
  set: (key: Key, value: Value) => void
  /**
   * Return flag if key exists
   */
  has: (key: Key) => boolean
  /**
   * Delete value for key
   */
  delete: (key: Key) => void
  /**
   * Clear cache
   */
  clear: () => void
}

export {}

类型声明

显示类型声明

typescript

type CacheKey = any
/**
 * Custom memoize cache handler
 */
export interface UseMemoizeCache<Key, Value> {
  /**
   * Get value for key
   */
  get: (key: Key) => Value | undefined
  /**
   * Set value for key
   */
  set: (key: Key, value: Value) => void
  /**
   * Return flag if key exists
   */
  has: (key: Key) => boolean
  /**
   * Delete value for key
   */
  delete: (key: Key) => void
  /**
   * Clear cache
   */
  clear: () => void
}
/**
 * Memoized function
 */
export interface UseMemoizeReturn<Result, Args extends unknown[]> {
  /**
   * Get result from cache or call memoized function
   */
  (...args: Args): Result
  /**
   * Call memoized function and update cache
   */
  load: (...args: Args) => Result
  /**
   * Delete cache of given arguments
   */
  delete: (...args: Args) => void
  /**
   * Clear cache
   */
  clear: () => void
  /**
   * Generate cache key for given arguments
   */
  generateKey: (...args: Args) => CacheKey
  /**
   * Cache container
   */
  cache: UseMemoizeCache<CacheKey, Result>
}
export interface UseMemoizeOptions<Result, Args extends unknown[]> {
  getKey?: (...args: Args) => string | number
  cache?: UseMemoizeCache<CacheKey, Result>
}
/**
 * Reactive function result cache based on arguments
 */
export declare function useMemoize<Result, Args extends unknown[]>(
  resolver: (...args: Args) => Result,
  options?: UseMemoizeOptions<Result, Args>,
): UseMemoizeReturn<Result, Args>