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August 19, 2024 16:55
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| type CacheType<T> = { | |
| has: (key: string) => boolean; | |
| get: (key: string) => T | undefined; | |
| set: (key: string, result: T, now?: number) => void; | |
| clear?: () => void; | |
| }; | |
| const createCache = <T>(maxAge = 60_000): CacheType<T> => { | |
| const values = new Map<string, T>(); | |
| const expiry = new Map<string, number>(); | |
| const set = (key: string, result: T, now = Date.now()) => { | |
| values.set(key, result); | |
| expiry.set(key, now + maxAge); | |
| }; | |
| const clear = (now = Date.now()) => { | |
| for (const [key, expiryTime] of expiry.entries()) { | |
| if (now >= expiryTime) { | |
| values.delete(key); | |
| expiry.delete(key); | |
| } | |
| } | |
| }; | |
| return { | |
| has: values.has, | |
| get: values.get, | |
| clear, | |
| set, | |
| }; | |
| }; | |
| const createTimeoutCache = <T>(maxAge = 60_000): CacheType<T> => { | |
| const values = new Map<string, T>(); | |
| const set = (key: string, result: T) => { | |
| values.set(key, result); | |
| const timer = setTimeout(() => { | |
| values.delete(key); | |
| }, maxAge); | |
| timer.unref?.(); | |
| }; | |
| return { | |
| has: values.has, | |
| get: values.get, | |
| set, | |
| clear: () => {}, | |
| }; | |
| }; | |
| interface MemoizeOptions<T, A extends unknown[]> { | |
| maxAge?: number; | |
| getKey?: (args: A) => string; | |
| /** | |
| * Override | |
| */ | |
| cache?: CacheType<T>; | |
| } | |
| const memoize = <T, A extends unknown[]>( | |
| fn: (...args: A) => T, | |
| options?: MemoizeOptions<T, A>, | |
| ) => { | |
| const { | |
| maxAge = 60_000, | |
| getKey = JSON.stringify, | |
| cache = createCache(maxAge), | |
| } = options || {}; | |
| return (...args: A) => { | |
| const key = getKey(args); | |
| const now = Date.now(); | |
| cache.clear?.(); | |
| if (cache.has(key)) { | |
| return cache.get(key) as T; | |
| } | |
| const result = fn(...args); | |
| cache.set(key, result, now); | |
| return result; | |
| }; | |
| }; | |
| const memoizePromise = <T, A extends unknown[]>( | |
| fn: (...args: A) => Promise<T>, | |
| options?: MemoizeOptions<T, A>, | |
| ) => { | |
| const { | |
| maxAge = 60_000, | |
| getKey = JSON.stringify, | |
| cache = createCache(maxAge), | |
| } = options || {}; | |
| return async (...args: A) => { | |
| const key = getKey(args); | |
| const now = Date.now(); | |
| cache.clear?.(); | |
| if (cache.has(key)) { | |
| return cache.get(key) as T; | |
| } | |
| const result = await fn(...args); | |
| cache.set(key, result, now); | |
| return result; | |
| }; | |
| }; | |
| // Usage example: | |
| const memoizedFunction = memoizePromise( | |
| async (query: string) => console.log(query), | |
| { | |
| // maxAge: 5000, | |
| cache: createTimeoutCache(), | |
| }, | |
| ); |
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