Obj-cached NPM

Object Cached Function

Cache function results in globalThis, useful when playing with bun --hot

Example Usage

Sync

import {objCached} from 'obj-cached'

// sync
const fn = objCached(() => {
    // do something heavy in sync
    // cached with global object
    return ...
}) // cached with globalThis by default, (global['prefix-hashedKeyXXXX'] in node or window['prefix-hashedKeyXXXX'] in browser)

const result = fn()

Async

// async
import {objCachedAsync} from 'obj-cached'
const cacheObj = {} // custom cacheObj
const fna =  objCachedAsync(async ()=> {
    // do something heavy
    // and cached with global object
    return ...
}, cacheObj) // cached with global this

const result = await fn()

Store your Cached Object into File (must by async)

import { FileCacheObj } from "file-cached";
import { objCachedAsync } from "obj-cached";

const cacheObj = FileCacheObj(import.meta.dir + "/cache.json");

const result = await objCachedAsync(async () => {
  // do sth heavy
}, cacheObj)();

Limitations

You can only cache plain JSON object
Use async version when used with FileCacheObj.
objCachedAsync is NOT waitting for cache written

so cache data MAY LOST if you terminate process before it's done.
and there are maybe conflict cache written

Implementation

export function objCached<Args extends unknown[], Result>(
  fn: (...args: Args) => Result,
  obj: Record<string, unknown> = globalThis,
  prefix = "obj-cached-"
) {
  const key = `${prefix}${fn.toString()}@${JSON.stringify(args)}`;
  return (...args: Args) => (obj[key] ??= fn(...args)) as Result;
}
export function objCachedAsync<Args extends unknown[], Result>(
  fn: (...args: Args) => Promise<Result> | Result,
  obj: Record<string, unknown> = globalThis,
  prefix = "obj-cached-"
) {
  const key = `${prefix}${fn.toString()}@${JSON.stringify(args)}`;
  return async (...args: Args) => (obj[key] ??= await fn(...args)) as Result;
}