import { Options } from '../internal/resolveValue.ts';
import { Observer } from '../Observer/Observer.ts';
/**
 * Local-storage-backed state management.
 * Data persists across browser sessions until explicitly cleared.
 */
export declare class LocalState extends Observer {
    static get<T = unknown>(key: string, options: Options<T> & {
        strict: true;
    }): T;
    static get<T = unknown>(key: string, options: Options<T> & {
        fallback: T;
    }): T;
    static get<T = unknown>(key: string, options?: Options<T>): T | undefined;
    /**
     * Stores a value in local storage.
     *
     * Always JSON-serialises. This is a deliberate change from the previous
     * implementation, which stored strings raw — that caused values like
     * `"42"` or `"true"` to come back as `42` and `true` after a roundtrip.
     *
     * @throws when the value cannot be serialised (circular refs, functions,
     *         symbols, undefined) or when localStorage refuses the write
     *         (QuotaExceededError, SecurityError).
     */
    static set<T = unknown>(key: string, value: T): void;
    /**
     * Removes a value from local storage.
     */
    static remove(key: string): void;
    /**
     * Clears every value in local storage and emits a `null` event for each removed key.
     */
    static clear(): void;
    static has(key: string): boolean;
}