type AnyFunction = (...arguments_: readonly any[]) => unknown; type CacheStorageContent = { data: ValueType; maxAge: number; }; type CacheStorage = { has: (key: KeyType) => boolean; get: (key: KeyType) => CacheStorageContent | undefined; set: (key: KeyType, value: CacheStorageContent) => void; delete: (key: KeyType) => void; clear?: () => void; }; export type Options = { /** Milliseconds until the cache expires. @default Infinity */ readonly maxAge?: number; /** Determines the cache key for storing the result based on the function arguments. By default, __only the first argument is considered__ and it only works with [primitives](https://developer.mozilla.org/en-US/docs/Glossary/Primitive). A `cacheKey` function can return any type supported by `Map` (or whatever structure you use in the `cache` option). You can have it cache **all** the arguments by value with `JSON.stringify`, if they are compatible: ``` import memoize from 'memoize'; memoize(function_, {cacheKey: JSON.stringify}); ``` Or you can use a more full-featured serializer like [serialize-javascript](https://github.com/yahoo/serialize-javascript) to add support for `RegExp`, `Date` and so on. ``` import memoize from 'memoize'; import serializeJavascript from 'serialize-javascript'; memoize(function_, {cacheKey: serializeJavascript}); ``` @default arguments_ => arguments_[0] @example arguments_ => JSON.stringify(arguments_) */ readonly cacheKey?: (arguments_: Parameters) => CacheKeyType; /** Use a different cache storage. Must implement the following methods: `.has(key)`, `.get(key)`, `.set(key, value)`, `.delete(key)`, and optionally `.clear()`. You could for example use a `WeakMap` instead or [`quick-lru`](https://github.com/sindresorhus/quick-lru) for a LRU cache. @default new Map() @example new WeakMap() */ readonly cache?: CacheStorage>; }; /** [Memoize](https://en.wikipedia.org/wiki/Memoization) functions - An optimization used to speed up consecutive function calls by caching the result of calls with identical input. @param fn - The function to be memoized. @example ``` import memoize from 'memoize'; let index = 0; const counter = () => ++index; const memoized = memoize(counter); memoized('foo'); //=> 1 // Cached as it's the same argument memoized('foo'); //=> 1 // Not cached anymore as the arguments changed memoized('bar'); //=> 2 memoized('bar'); //=> 2 ``` */ export default function memoize(fn: FunctionToMemoize, { cacheKey, cache, maxAge, }?: Options): FunctionToMemoize; /** @returns A [decorator](https://github.com/tc39/proposal-decorators) to memoize class methods or static class methods. @example ``` import {memoizeDecorator} from 'memoize'; class Example { index = 0 @memoizeDecorator() counter() { return ++this.index; } } class ExampleWithOptions { index = 0 @memoizeDecorator({maxAge: 1000}) counter() { return ++this.index; } } ``` */ export declare function memoizeDecorator(options?: Options): (target: any, propertyKey: string, descriptor: PropertyDescriptor) => void; /** Clear all cached data of a memoized function. @param fn - The memoized function. */ export declare function memoizeClear(fn: AnyFunction): void; export {};