@lucianojd/recoil-sync-next/src/utils/initializableAtomFamily.ts

recoil-sync stores for Next.js

import {
  SerializableParam,
  atomFamily,
  selectorFamily,
  RecoilState,
  AtomFamilyOptions,
} from 'recoil'

export function initializableAtomFamily<
  T extends SerializableParam,
  P extends SerializableParam
>(
  options: Omit<AtomFamilyOptions<T, P>, 'default'>
): (param: P, initialValue: T) => RecoilState<T> {
  const baseAtom: (param: P) => RecoilState<T> = atomFamily<T, P>({
    ...options,
    default: undefined,
  })

  const evaluationSelector = selectorFamily<T, { param: P; initialValue: T }>({
    key: `${options.key}::withInitialValue`,
    get:
      ({ param, initialValue }) =>
      ({ get }) =>
        get(baseAtom(param)) ?? initialValue,
    set:
      ({ param }) =>
      ({ set }, newValue) =>
        set(baseAtom(param), newValue),
  })

  return (param, initialValue) => {
    return evaluationSelector({ param, initialValue })
  }
}