memoize

import { memoize } from "jsr:@ende/cache";

function · experimental

function memoize<Fn extends (...args: never[]) => unknown, Key = string, Cache extends MemoizationCache<Key, MemoizationCacheResult<ReturnType<Fn>>> = Map<Key, MemoizationCacheResult<ReturnType<Fn>>>>(fn: Fn, options?: MemoizeOptions<Fn, Key, Cache>): Fn & { cache: Cache }

Cache the results of a function based on its arguments.

fn: Fn: The function to memoize
options?: MemoizeOptions<Fn, Key, Cache>: Options for memoization

Returns

The memoized function, with a cache property exposing the underlying cache for inspection or manual invalidation.

Example: Basic usage

import { memoize } from "@ende/cache";
import { assertEquals } from "@ende/assert";

// fibonacci function, which is very slow for n > ~30 if not memoized
const fib = memoize((n: bigint): bigint => {
  return n <= 2n ? 1n : fib(n - 1n) + fib(n - 2n);
});

assertEquals(fib(100n), 354224848179261915075n);

Note

By default, memoization is on the basis of all arguments passed to the function, with equality determined by reference. This means that, for example, passing a memoized function as arr.map(func) will not use the cached results, as the index is implicitly passed as an argument. To avoid this, you can pass a custom getKey option or use the memoized function inside an anonymous callback like arr.map((x) => func(x)).

Source