PageRevealEvent

function reveal() {
  // Include startup animation here
}
/* This will fire in the first rendered frame after loading */
requestAnimationFrame(() => reveal());

/* This will fire if the page is restored from BFCache */
window.onpagehide = () => requestAnimationFrame(() => reveal());

window.addEventListener("pagereveal", async (e) => {
  // If the "from" history entry does not exist, return
  if (!navigation.activation.from) return;

  // Only run this if an active view transition exists
  if (e.viewTransition) {
    const fromUrl = new URL(navigation.activation.from.url);
    const currentUrl = new URL(navigation.activation.entry.url);

    // Went from profile page to homepage
    // ~> Set VT names on the relevant list item
    if (isProfilePage(fromUrl) && isHomePage(currentUrl)) {
      const profile = extractProfileNameFromUrl(fromUrl);

      // Set view-transition-name values on the elements to animate
      document.querySelector(`#${profile} span`).style.viewTransitionName =
        "name";
      document.querySelector(`#${profile} img`).style.viewTransitionName =
        "avatar";

      // Remove names after snapshots have been taken
      // so that we're ready for the next navigation
      await e.viewTransition.ready;
      document.querySelector(`#${profile} span`).style.viewTransitionName =
        "none";
      document.querySelector(`#${profile} img`).style.viewTransitionName =
        "none";
    }

    // Went to profile page
    // ~> Set VT names on the main title and image
    if (isProfilePage(currentUrl)) {
      // Set view-transition-name values on the elements to animate
      document.querySelector(`#detail main h1`).style.viewTransitionName =
        "name";
      document.querySelector(`#detail main img`).style.viewTransitionName =
        "avatar";

      // Remove names after snapshots have been taken
      // so that we're ready for the next navigation
      await e.viewTransition.ready;
      document.querySelector(`#detail main h1`).style.viewTransitionName =
        "none";
      document.querySelector(`#detail main img`).style.viewTransitionName =
        "none";
    }
  }
});