effector persistent store

effector persistent store.js

//@flow

import {
  createStore,
  createEffect,
  type Store,
} from 'effector'

export function persistentStore(defaults: string, key: string) {
  const readEff = createEffect(`read ${key}`)
  const writeEff = createEffect(`write ${key}`)
  readEff.use((_?: void) => {
    try {
      return localStorage.getItem(key)
    } catch (error) {
      return null
    }
  })
  writeEff.use((value: string | null) => {
    try {
      if (value == null) localStorage.removeItem(key)
      else localStorage.setItem(key, value)
    } catch (error) {}
  })
  const store = createStore(defaults)
  store
    .on(readEff.done, (state, {result}) => result)
    .on(writeEff, (_, upd: string | null) => upd)
  return {
    store,
    write: writeEff,
    read: readEff,
    clear: writeEff.prepend((_?: void) => null),
  }
}