Jotai's selectorFamily creating explaination 🙏🙏

[kaustubh2525]

I just wanna know the explaination on how would i create a selectorFamily in jotai in such a way just like recoil's selectorFamily which takes in the args and specifically derives the piece of data / state for some usage with a small example ??

[dai-shi]

Jotai's atomFamily has a different signature from Recoil's one and should cover both atomFamily and selectorFamily use cases of Recoil. It's not the same, and there might be some capabilities missing.

import { atomFamily } from 'jotai/utils';

const baseAtom = atom({});
const myFamily = atomFamily((key) => atom((get) => get(baseAtom)[key]));

FYI, Jotai's atomFamily implementation is pretty simple. See this simplified code:
#1323 (reply in thread)

// simplified code
const atomFamily = (initializeAtom) => {
  const cache = new Map();
  return (param) => {
    if (!cache.has(param)) {
      cache.set(param, initializeAtom(param));
    }
    return cache.get(param);
  };
};