detect-tab/src/utils.test.ts

A comprehensive tab detection and management library for web applications

/**
 * @jest-environment jsdom
 */

import {
  isVisibilityAPISupported,
  isBrowserSupported,
  getVisibilityProperties,
  debounce,
  now,
  formatDuration,
  safeJSONParse,
  isStorageAvailable
} from './utils';

describe('Utils', () => {
  describe('isVisibilityAPISupported', () => {
    it('should return true when document.visibilityState exists', () => {
      expect(isVisibilityAPISupported()).toBe(true);
    });
  });

  describe('isBrowserSupported', () => {
    it('should return true in browser environment', () => {
      expect(isBrowserSupported()).toBe(true);
    });
  });

  describe('getVisibilityProperties', () => {
    it('should return standard property names', () => {
      const props = getVisibilityProperties();
      expect(props.hidden).toBe('hidden');
      expect(props.visibilityChange).toBe('visibilitychange');
    });
  });

  describe('debounce', () => {
    jest.useFakeTimers();

    afterEach(() => {
      jest.clearAllTimers();
    });

    it('should debounce function calls', () => {
      const mockFn = jest.fn();
      const debouncedFn = debounce(mockFn, 100);

      debouncedFn();
      debouncedFn();
      debouncedFn();

      expect(mockFn).not.toHaveBeenCalled();

      jest.advanceTimersByTime(100);
      expect(mockFn).toHaveBeenCalledTimes(1);
    });

    it('should pass arguments to debounced function', () => {
      const mockFn = jest.fn();
      const debouncedFn = debounce(mockFn, 100);

      debouncedFn('arg1', 'arg2');
      jest.advanceTimersByTime(100);

      expect(mockFn).toHaveBeenCalledWith('arg1', 'arg2');
    });
  });

  describe('now', () => {
    it('should return current timestamp', () => {
      const timestamp = now();
      expect(typeof timestamp).toBe('number');
      expect(timestamp).toBeGreaterThan(0);
    });
  });

  describe('formatDuration', () => {
    it('should format seconds', () => {
      expect(formatDuration(5000)).toBe('5s');
    });

    it('should format minutes and seconds', () => {
      expect(formatDuration(65000)).toBe('1m 5s');
    });

    it('should format hours, minutes and seconds', () => {
      expect(formatDuration(3665000)).toBe('1h 1m 5s');
    });

    it('should format days, hours, minutes and seconds', () => {
      expect(formatDuration(90065000)).toBe('1d 1h 1m 5s');
    });
  });

  describe('safeJSONParse', () => {
    it('should parse valid JSON', () => {
      const obj = { test: 'value' };
      const result = safeJSONParse(JSON.stringify(obj), {});
      expect(result).toEqual(obj);
    });

    it('should return fallback for invalid JSON', () => {
      const fallback = { fallback: true };
      const result = safeJSONParse('invalid json', fallback);
      expect(result).toEqual(fallback);
    });

    it('should return fallback for null JSON', () => {
      const fallback = { fallback: true };
      const result = safeJSONParse('null', fallback);
      expect(result).toEqual(fallback);
    });
  });

  describe('isStorageAvailable', () => {
    it('should return true when localStorage is available', () => {
      expect(isStorageAvailable()).toBe(true);
    });

    it('should handle storage errors gracefully', () => {
      const originalSetItem = Storage.prototype.setItem;
      Storage.prototype.setItem = jest.fn(() => {
        throw new Error('Storage error');
      });

      expect(isStorageAvailable()).toBe(false);

      Storage.prototype.setItem = originalSetItem;
    });
  });
});