class LocalStorageMock { private store: object; constructor() { this.store = {}; } public clear() { this.store = {}; } public getItem(key) { return this.store[key]; } public setItem(key, value) { this.store[key] = value.toString(); } public removeItem(key) { delete this.store[key]; } } Object.defineProperty(window, 'localStorage', { value: new LocalStorageMock() });