Store

The store is the runtime container for Amos state.

import { createStore } from 'amos';

const store = createStore();

In React apps, you usually create one store and pass it to <Provider />.

<Provider store={store}>
  <App />
</Provider>

Selecting State

Use select to read a box or selector.

const count = store.select(countBox);
const label = store.select(selectCountLabel());

Selecting a box mounts it lazily. On first select, Amos stores the box initial state in the store snapshot.

const countBox = numberBox('count', 1);

store.snapshot(); // {}
store.select(countBox); // 1
store.snapshot(); // { count: 1 }

Use dispatch to apply mutations, actions, and signals.

store.dispatch(countBox.add(1));
store.dispatch(loadUser(1));
store.dispatch(signOutSignal({ userId: 1 }));

Dispatch returns the value produced by the dispatchable. A mutation returns the new box state. An action returns whatever its actor returns.

Arrays are supported by the built-in batch enhancer.

store.dispatch([countBox.add(1), openBox.close()]);

const [count, open] = store.select([countBox, openBox]);

Subscribers are notified once after the root dispatch finishes.

const snapshot = store.snapshot();

The snapshot is the internal state object keyed by box key. Treat it as read-only. It is useful for SSR, persistence, debugging, and tests.

const unsubscribe = store.subscribe(() => {
  console.log(store.snapshot());
});

unsubscribe();

The listener runs after a root dispatch completes. Nested dispatches do not notify until control returns to the root dispatch.

const store = createStore({
  name: 'My app',
  devtools: true,
  preloadedState: {
    count: 10,
  },
});

name labels the store in devtools.

devtools controls Redux DevTools integration.

preloadedState is JSON-like state keyed by box key. Amos converts it back to the shape of the initial state when a box mounts.

You can pass store enhancers after options.

const store = createStore({}, withPersist({ storage }));

Amos applies its built-in enhancers first, then your custom enhancers.