/
memoize.ts
57 lines (53 loc) · 1.48 KB
/
memoize.ts
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/**
* Create a cache key from an array of arguments
* @param args
* @returns
*/
const createCacheKeyFromArgs = (args: any[]) =>
args.reduce(
(cacheKey, arg) =>
(cacheKey += `_${
typeof arg === "object" ? JSON.stringify(args) : `${arg}`
}_`),
""
);
let memoizedFnCache: Record<string, any> = {};
/**
* Wrap a function into a memoized version of itself. Multiple calls for the same function
* will return the same memoized function - thus enabling a shared cache of results.
* `const memoizedItemSearch = memoize(searchItems);`
* @param fn
* @returns
*/
export const memoize = <ARGS extends unknown[], RET>(
fn: (...args: ARGS) => RET
) => {
if (!memoizedFnCache[`_${fn.name}`]) {
const cache: Record<string, RET> = {};
const memoizedFn = (...args: ARGS) => {
const cacheKey = createCacheKeyFromArgs(args);
if (cache[cacheKey]) {
return cache[cacheKey];
}
const asyncFn = fn.call(undefined, ...args);
cache[cacheKey] = asyncFn;
return asyncFn;
};
memoizedFnCache[`_${fn.name}`] = memoizedFn;
}
return memoizedFnCache[`_${fn.name}`];
};
/**
* Clear the cache of a memoized function
* If no function name is provided, the entire cache is cleared
* This is useful for testing, but should not be used in production
* @param fn
*/
export const clearMemoizedCache = (fnName?: string) => {
if (!fnName) {
memoizedFnCache = {};
return;
} else {
delete memoizedFnCache[`_${fnName}`];
}
};