p-memoize
- Version 7.1.1
- Published
- 16.2 kB
- 2 dependencies
- MIT license
Install
npm i p-memoize
yarn add p-memoize
pnpm add p-memoize
Overview
Memoize promise-returning & async functions
Index
Functions
Type Aliases
Functions
function pMemoize
pMemoize: <FunctionToMemoize extends AnyAsyncFunction, CacheKeyType>( fn: FunctionToMemoize, { cacheKey, cache }?: Options<FunctionToMemoize, CacheKeyType>) => FunctionToMemoize;
[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.
Parameter fn
Function to be memoized.
Example 1
import {setTimeout as delay} from 'node:timer/promises';import pMemoize from 'p-memoize';import got from 'got';const memoizedGot = pMemoize(got);await memoizedGot('https://sindresorhus.com');// This call is cachedawait memoizedGot('https://sindresorhus.com');await delay(2000);// This call is not cached as the cache has expiredawait memoizedGot('https://sindresorhus.com');
function pMemoizeClear
pMemoizeClear: (fn: AnyAsyncFunction) => void;
Clear all cached data of a memoized function.
Parameter fn
Memoized function.
function pMemoizeDecorator
pMemoizeDecorator: <FunctionToMemoize extends AnyAsyncFunction, CacheKeyType>( options?: Options<FunctionToMemoize, CacheKeyType>) => (target: any, propertyKey: string, descriptor: PropertyDescriptor) => void;
- Only class methods and getters/setters can be memoized, not regular functions (they aren't part of the proposal); - Only [TypeScript’s decorators](https://www.typescriptlang.org/docs/handbook/decorators.html#parameter-decorators) are supported, not [Babel’s](https://babeljs.io/docs/en/babel-plugin-proposal-decorators), which use a different version of the proposal; - Being an experimental feature, they need to be enabled with
--experimentalDecorators
; follow TypeScript’s docs.Returns
A [decorator](https://github.com/tc39/proposal-decorators) to memoize class methods or static class methods.
Example 1
import {pMemoizeDecorator} from 'p-memoize';class Example {index = 0@pMemoizeDecorator()async counter() {return ++this.index;}}class ExampleWithOptions {index = 0@pMemoizeDecorator()async counter() {return ++this.index;}}
Type Aliases
type AnyAsyncFunction
type AnyAsyncFunction = (...arguments_: readonly any[]) => Promise<unknown | void>;
type CacheStorage
type CacheStorage<KeyType, ValueType> = { has: (key: KeyType) => Promise<boolean> | boolean; get: (key: KeyType) => Promise<ValueType | undefined> | ValueType | undefined; set: (key: KeyType, value: ValueType) => Promise<unknown> | unknown; delete: (key: KeyType) => unknown; clear?: () => unknown;};
type Options
type Options<FunctionToMemoize extends AnyAsyncFunction, CacheKeyType> = { /** 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 pMemoize from 'p-memoize';
pMemoize(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 pMemoize from 'p-memoize'; import serializeJavascript from 'serialize-javascript';
pMemoize(function_, {cacheKey: serializeJavascript}); ```
@default arguments_ => arguments_[0] @example arguments_ => JSON.stringify(arguments_) */ readonly cacheKey?: (arguments_: Parameters<FunctionToMemoize>) => 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. To disable caching so that only concurrent executions resolve with the same value, pass `false`.
@default new Map() @example new WeakMap() */ readonly cache?: | CacheStorage<CacheKeyType, AsyncReturnType<FunctionToMemoize>> | false;};
Package Files (1)
Dependencies (2)
Dev Dependencies (11)
Peer Dependencies (0)
No peer dependencies.
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