/**
 * The shared coin wallet. One total, persisted in localStorage, synced across
 * tabs, and mirrored into every `[data-px-coins]` element on the page.
 */
type Listener = (total: number) => void;
declare function read(): number;
export declare const coins: {
    get: typeof read;
    /** Award (or with a negative amount, spend) coins. Never drops below zero. */
    add(amount: number): number;
    set(total: number): number;
    reset(): void;
    /** Returns an unsubscribe function. */
    subscribe(listener: Listener): () => void;
};
export {};