page-visibility.js

let pageVisible = true;

function updatePageVisibility(e) {
  if (e.type === "visibilitychange") {
    pageVisible = !document.hidden;
  } else {
    const typeVisibilityMap = { blur: false, focus: true, pagehide: false, pageshow: true };
    pageVisible = typeVisibilityMap[e.type];
  }
}

document.addEventListener("visibilitychange", updatePageVisibility);
window.addEventListener("focus", updatePageVisibility);
window.addEventListener("blur", updatePageVisibility);
window.addEventListener("pagehide", updatePageVisibility);
window.addEventListener("pageshow", updatePageVisibility);