export interface Item {
    id: string;
    quantity: number;
}
export interface Cart<I extends Item> {
    id: string;
    items: I[];
}
export declare const createCartStore: <C extends Cart<Item>>(defaultCart: C, onValidate?: ((value: C) => Promise<C | null>) | undefined, namespace?: string) => {
    getItem: (id: string) => Item | undefined;
    addItem: (item: Item) => void;
    updateItemQuantity: (id: string, quantity: number) => void;
    removeItem: (id: string) => void;
    emptyCart: () => void;
    inCart: (id: string) => boolean;
    isEmpty: () => boolean;
    set: (val: C) => void;
    read: () => C;
    readInitial: () => C;
    subscribe: (sub: (value: C) => void | (() => void)) => () => void;
};