Implementation of resource cache based on MobX, which supports automatically generation and release to avoid memory leak.

If delay field is specified (including zero), the cache is retained until delay millisecond after func(...args) is unobserved or untracked access is performed.

If delay field is not specified, the cache is retained while func(...args) is observed, and untracked access is not cached.

Supports MobX5, MobX6. This library uses only mobx.createAtom of MobX and is independent of annotation/decorator implementation.

import { resourceCache } from "mobx-resource-cache";

// prerequisite
class MobXFetch<T> {
  @observable promise: Promise<T> | T;
  constructor(url: string) {
    this.promise = (async () => {
      const response = await fetch(url);
      const value = await response.json();
      this.promise = value;
      return value;
    })();
  }
  close() {}
}
const mobxFetch = (url: string) => new MobXFetch(url);

// main
const cache = resourceCache({
  delay: 60000,
  get: (url: string) => mobxFetch,
  cleanUpFn: (item: MobXFetch<unknown>) => {
    item.close();
  },
});

If you are looking for memoization of function, consider mobx-memo