/** Pure state transition: returns the next state for an action, never mutates. */
export type Reducer<S, A> = (state: S, action: A) => S;
/** Change subscriber invoked with the new state and the state it replaced. */
export type StoreListener<S> = (state: S, prev: S) => void;
/**
 * Minimal serializable store — the single writer of app state. The frame loop
 * reads state and writes scene objects, never the reverse.
 */
export interface Store<S, A = Partial<S>> {
    get(): S;
    /** Shallow-merge a patch into the state and notify subscribers. */
    set(patch: Partial<S>): void;
    /** Run the reducer. Throws when the store was created without one. */
    dispatch(action: A): void;
    /** Listen for state changes; returns an unsubscribe function. */
    subscribe(listener: StoreListener<S>): () => void;
}
/**
 * Create a minimal store holding serializable app state. `set` shallow-merges
 * a patch; `dispatch` runs the optional reducer; listeners fire only when the
 * committed state is a new object reference (reducers may return the same
 * state to signal no change).
 *
 * @param initial - Starting state. Keep it JSON-serializable (tuples, not
 * `Vector3`s) so it can be persisted and replayed.
 * @param reducer - Optional {@link Reducer} enabling `dispatch`; without one,
 * `dispatch` throws.
 * @returns A {@link Store}.
 */
export declare function createStore<S extends object, A = Partial<S>>(initial: S, reducer?: Reducer<S, A>): Store<S, A>;
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