96 lines
2.5 KiB
TypeScript
96 lines
2.5 KiB
TypeScript
declare namespace mem {
|
|
interface CacheStorage<KeyType extends unknown, ValueType extends unknown> {
|
|
has(key: KeyType): boolean;
|
|
get(key: KeyType): ValueType | undefined;
|
|
set(key: KeyType, value: ValueType): void;
|
|
delete(key: KeyType): void;
|
|
clear?: () => void;
|
|
}
|
|
|
|
interface Options<
|
|
ArgumentsType extends unknown[],
|
|
CacheKeyType extends unknown,
|
|
ReturnType extends unknown
|
|
> {
|
|
/**
|
|
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, if there's only one argument and it's a [primitive](https://developer.mozilla.org/en-US/docs/Glossary/Primitive), it's used directly as a key, otherwise it's all the function arguments JSON stringified as an array.
|
|
|
|
You could for example change it to only cache on the first argument `x => JSON.stringify(x)`.
|
|
*/
|
|
readonly cacheKey?: (...arguments: ArgumentsType) => CacheKeyType;
|
|
|
|
/**
|
|
Use a different cache storage. You could for example use a `WeakMap` instead or [`quick-lru`](https://github.com/sindresorhus/quick-lru) for a LRU cache.
|
|
|
|
@default new Map()
|
|
*/
|
|
readonly cache?: CacheStorage<CacheKeyType, {data: ReturnType; maxAge: number}>;
|
|
|
|
/**
|
|
Cache rejected promises.
|
|
|
|
@default false
|
|
*/
|
|
readonly cachePromiseRejection?: boolean;
|
|
}
|
|
}
|
|
|
|
declare const mem: {
|
|
/**
|
|
[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 - Function to be memoized.
|
|
|
|
@example
|
|
```
|
|
import mem = require('mem');
|
|
|
|
let i = 0;
|
|
const counter = () => ++i;
|
|
const memoized = mem(counter);
|
|
|
|
memoized('foo');
|
|
//=> 1
|
|
|
|
// Cached as it's the same arguments
|
|
memoized('foo');
|
|
//=> 1
|
|
|
|
// Not cached anymore as the arguments changed
|
|
memoized('bar');
|
|
//=> 2
|
|
|
|
memoized('bar');
|
|
//=> 2
|
|
```
|
|
*/
|
|
<
|
|
ArgumentsType extends unknown[],
|
|
ReturnType extends unknown,
|
|
CacheKeyType extends unknown
|
|
>(
|
|
fn: (...arguments: ArgumentsType) => ReturnType,
|
|
options?: mem.Options<ArgumentsType, CacheKeyType, ReturnType>
|
|
): (...arguments: ArgumentsType) => ReturnType;
|
|
|
|
/**
|
|
Clear all cached data of a memoized function.
|
|
|
|
@param fn - Memoized function.
|
|
*/
|
|
clear<ArgumentsType extends unknown[], ReturnType extends unknown>(
|
|
fn: (...arguments: ArgumentsType) => ReturnType
|
|
): void;
|
|
|
|
// TODO: Remove this for the next major release
|
|
default: typeof mem;
|
|
};
|
|
|
|
export = mem;
|