@studnicky/store

Keep application state observable while selecting an in-memory or browser-native persistence target.

Install

pnpm add @studnicky/store

Core store

Store<TState> owns one named state value. setState and update persist before notifying subscribers; hydrate restores the named value; and clear removes it before publishing the initial state.

const persistence = MemoryPersistence.create<number>();
const store = Store.create({ 'initialState': 0, 'key': 'demo:memory-counter', 'persistence': persistence });

store.subscribe((snapshot): void => {
  console.log(`subscriber received ${snapshot}`);
});

await store.update((snapshot): number => {
  const result = snapshot + 1;
  return result;
});

const hydrated = Store.create({ 'initialState': 0, 'key': 'demo:memory-counter', 'persistence': persistence });

await hydrated.hydrate();

console.log({
  'hydrated': hydrated.getSnapshot(),
  'snapshot': store.getSnapshot()
});

Try it

Memory state

This example updates a state value, observes the notification, then creates a second Store with the same persistence to hydrate the value.

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Browser persistence targets

BrowserPersistence has the same StatePersistenceInterface<TState> contract as MemoryPersistence. Select Memory, LocalStorage, SessionStorage, or IndexedDb; the browser adapter uses the corresponding native API directly.

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The runnable sample writes, hydrates, reports, and clears one counter for every target, so it leaves the browser storage area clean.

Composition seams

Surface	Consumer use
StoreInterface<TState>	Depend on a state container without coupling to a concrete implementation.
StatePersistenceInterface<TState>	Supply a persistence adapter for another environment or backing service.
StateCodecInterface<TState>	Validate and serialize persisted values at the storage boundary.
MemoryPersistence<TState>	Keep transient state in process memory.
BrowserPersistence<TState>	Persist state through a browser-native target.
StorageTarget	Select Memory, LocalStorage, SessionStorage, or IndexedDb.

Exports

Symbol	Purpose	Import path
Store	Observable state container with serialized writes.	@studnicky/store
MemoryPersistence	In-memory persistence adapter.	@studnicky/store
JsonStateCodec	JSON serialization and caller-provided decoded-value validation.	@studnicky/store
StoreInterface	Store contract for consumer dependencies and composition.	@studnicky/store
StoreListenerInterface	Subscriber callback contract for store state updates.	@studnicky/store
StatePersistenceInterface	Persistence port implemented by storage adapters.	@studnicky/store
StateCodecInterface	Codec contract for persisted values.	@studnicky/store
BrowserPersistence	Browser-native persistence adapter.	@studnicky/store/browser
StorageTarget	Browser persistence target selector.	@studnicky/store/browser

Layered state

Use @studnicky/strata-store-kit to connect a fast in-memory store to a durable browser store while retaining the StoreInterface<TState> API.

Source on GitHub