/// <reference lib="es2023" preserve="true" />
/// <reference lib="dom" preserve="true" />
import type { StringMap } from './types.js';
/**
 * Implements WebStorage API by using in-memory storage.
 * Can be useful in SSR environment or unit tests.
 *
 * This is how localStorage can be mocked in Node:
 *
 * Object.assign(globalThis, {
 *  localStorage: new InMemoryWebStorage(),
 * })
 *
 * @experimental
 */
export declare class InMemoryWebStorage implements Storage {
    data: StringMap;
    constructor(data?: StringMap);
    getItem(key: string): string | null;
    setItem(key: string, value: string): void;
    removeItem(key: string): void;
    key(index: number): string | null;
    clear(): void;
    get length(): number;
}