react-sessionstorage-ttl-hook/src/useSessionStorageWithTTL.test.ts

React hook for sessionStorage with TTL and auto-expiry

import { renderHook, act } from '@testing-library/react-hooks';
import useSessionStorageWithTTL from './useSessionStorageWithTTL';

describe('useSessionStorageWithTTL', () => {
  beforeEach(() => {
    sessionStorage.clear();
    jest.useFakeTimers();
  });

  afterEach(() => {
    jest.runOnlyPendingTimers();
    jest.useRealTimers();
  });

  it('should return default value initially', () => {
    const { result } = renderHook(() =>
      useSessionStorageWithTTL('key1', 'default', 1000)
    );
    expect(result.current[0]).toBe('default');
  });

  it('should store and retrieve value', () => {
    const { result, rerender } = renderHook(() =>
      useSessionStorageWithTTL('key2', 'default', 1000)
    );

    act(() => {
      result.current[1]('newValue');
    });

    rerender();

    const stored = JSON.parse(sessionStorage.getItem('key2')!);
    expect(stored.value).toBe('newValue');
    expect(result.current[0]).toBe('newValue');
  });

  it('should auto-expire after TTL', () => {
    const { result, rerender } = renderHook(() =>
      useSessionStorageWithTTL('key3', 'default', 1000)
    );

    act(() => {
      result.current[1]('expiringValue');
    });

    rerender();

    expect(result.current[0]).toBe('expiringValue');

    act(() => {
      jest.advanceTimersByTime(1001);
    });

    rerender();

    const expired = sessionStorage.getItem('key3');
    expect(expired).toBeNull();
  });

  it('should ignore invalid JSON', () => {
    sessionStorage.setItem('key4', '{invalid json');
    const { result } = renderHook(() =>
      useSessionStorageWithTTL('key4', 'fallback', 1000)
    );
    expect(result.current[0]).toBe('fallback');
  });

  it('should skip all logic in SSR (no window)', () => {
    const originalWindow = global.window;
    // @ts-ignore
    delete global.window;

    const { result } = renderHook(() =>
      useSessionStorageWithTTL('keySSR', 'defaultSSR', 1000)
    );
    expect(result.current[0]).toBe('defaultSSR');

    global.window = originalWindow;
  });
});