isFullscreen

1/**
2 * Checks if the document is currently in fullscreen mode.
3 *
4 * @returns True if fullscreen is active, false otherwise.
5 */
6export function isFullscreen(): boolean {
7  if (typeof document === 'undefined') return false;
8
9  return !!(
10    document.fullscreenElement ||
11    (document as any).webkitFullscreenElement ||
12    (document as any).mozFullScreenElement ||
13    (document as any).msFullscreenElement
14  );
15}

1test('isFullscreen - returns true if document.fullscreenElement exists', () => {
2  const original = document.fullscreenElement;
3  Object.defineProperty(document, 'fullscreenElement', {
4    configurable: true,
5    value: {},
6  });
7
8  expect(isFullscreen()).toBe(true);
9
10  Object.defineProperty(document, 'fullscreenElement', {
11    configurable: true,
12    value: original,
13  });
14});
15
16test('isFullscreen - returns false if no fullscreen properties are set', () => {
17  const original = document.fullscreenElement;
18  Object.defineProperty(document, 'fullscreenElement', {
19    configurable: true,
20    value: null,
21  });
22
23  expect(isFullscreen()).toBe(false);
24
25  Object.defineProperty(document, 'fullscreenElement', {
26    configurable: true,
27    value: original,
28  });
29});