Pinafore-Web-Client-Frontend/routes/_utils/fullscreen.js

export const isFullscreen = () => !!(document.fullscreenElement ||
  document.webkitFullscreenElement ||
  document.mozFullScreenElement);

export const attachFullscreenListener = (listener) => {
  if ('onfullscreenchange' in document) {
    document.addEventListener('fullscreenchange', listener);
  } else if ('onwebkitfullscreenchange' in document) {
    document.addEventListener('webkitfullscreenchange', listener);
  } else if ('onmozfullscreenchange' in document) {
    document.addEventListener('mozfullscreenchange', listener);
  }
};

export const detachFullscreenListener = (listener) => {
  if ('onfullscreenchange' in document) {
    document.removeEventListener('fullscreenchange', listener);
  } else if ('onwebkitfullscreenchange' in document) {
    document.removeEventListener('webkitfullscreenchange', listener);
  } else if ('onmozfullscreenchange' in document) {
    document.removeEventListener('mozfullscreenchange', listener);
  }
};