persist-jotai

name	persist-jotai
description	Persist a jotai WritableAtom via createStore with @stainless-code/persist (persistAtom). Use when wiring jotai atoms to localStorage/sessionStorage/IndexedDB, or when default replace-merge for primitive atoms matters.
license	MIT
metadata	{"type":"composition","library":"@stainless-code/persist","library_version":"0.4.1","framework":"jotai"}
sources	["stainless-code/persist:src/adapters/sources/jotai.ts","stainless-code/persist:docs/architecture.md"]

Persisting jotai

@stainless-code/persist/sources/jotai persists a WritableAtom through a jotai Store (createStore() → { get, set, sub }).

When to use this skill

• You own a writable jotai atom and a store, and want reload survival.
• Atom values may be primitives — default merge must replace, not shallow-spread.

Zustand / TanStack Store → those persist-* skills. Hand-rolled → persistSource.

Install

bun add @stainless-code/persist jotai

jotai is an optional peer of /sources/jotai.

Minimal wiring

import { atom, createStore } from "jotai";
import { createJSONStorage } from "@stainless-code/persist";
import { persistAtom } from "@stainless-code/persist/sources/jotai";

const themeAtom = atom<"light" | "dark">("light");
const store = createStore();
const persist = persistAtom(store, themeAtom, {
  name: "app:theme:v1",
  storage: createJSONStorage(() => localStorage),
});

Needs both store and atom. Provider-only / atom-without-store is not enough.

Replace-merge default

Default merge is (persisted) => persisted. Shallow-spreading a primitive corrupts it ({...number} → {}). Pass your own merge for object atoms that need spread-merge. Override uses ??, so merge: undefined still replace-merges.

Common mistakes

• Omitting createStore. persistAtom(store, atom, opts) — store first.
• Readonly / computed atoms. Typed as WritableAtom only — no runtime throw (unlike TanStack persistAtom).
• Assuming object shallow-merge. Primitives need replace (the default).

API surface

• persistAtom(store, atom, options) → PersistApi
• Options / PersistApi: see skill persist. Replace-merge also used by TanStack persistAtom (persist-tanstack-store).