export declare let storage: {
    /** 通过 key 获取字符串类型的值，不存在时返回空字符串 ('') */
    getstr<TString extends string = string>(key: string): TString;
    /** 将字符串类型的值保存到 key */
    setstr(key: string, value?: string): void;
    /** 根据 key 获取 JSON 类型的值，不存在时返回通过第二个参数传入的默认值，默认为 null */
    get<TValue = any>(key: string, _default?: TValue): TValue;
    /** 保存 JSON 类型的值到 key, 并返回 value */
    set<TValue>(key: string, value: TValue): TValue;
    list(): string[];
    delete(key: string): void;
    set_bool(key: string, value: any): void;
    get_bool(key: string): boolean | undefined;
};
export declare let db: {
    store_name: 'kv-store';
    db: IDBDatabase;
    wait_request<TResult>(request: IDBOpenDBRequest | IDBRequest): Promise<TResult>;
    open(): Promise<void>;
    transaction(mode: IDBTransactionMode): IDBObjectStore;
    get<TReturn = any>(key: IDBValidKey): Promise<TReturn>;
    set(key: IDBValidKey, value: any): Promise<void>;
    delete(key: string): Promise<void>;
};