/**
 * In mobile Safari, the user may turn on "Block All Cookies".
 * In such situation, accessing to localStorage/sessionStorage will throw error.
 */
type ClearOptions = {
    keys: string[] | ((key: string) => boolean);
} | {
    exceptKeys: string[] | ((key: string) => boolean);
};
export declare class StorageHelper {
    private readonly storage;
    private static readonly trueBoolValue;
    private static readonly falseBoolValue;
    private globalPrefix;
    constructor(storage: Storage);
    setGlobalPrefix(prefix: string): void;
    clear(options?: ClearOptions): void;
    setBool(key: string, value: boolean): void;
    setString(key: string, value: string): void;
    setNumber(key: string, value: number): void;
    setObject<T extends object>(key: string, item: T): void;
    getBool(key: string, defaultValue: boolean): boolean;
    getString<T extends string = string>(key: string, defaultValue: T, validValues?: readonly T[]): T;
    getNumber(key: string, defaultValue: number, validator?: number[] | ((value: number) => boolean)): number;
    getObject<T extends object>(key: string, defaultValue: T, validator: (item: object) => boolean): T;
    getRaw(key: string): string | null;
    private set;
    private get;
    private forEach;
}
export {};