Function navigate

packages/dev/s2-docs/src/client.tsx:65–199

(pathname: string, push = false, popstateState: HistoryState | null = null)

// and in a React transition, stream in the new page. Once complete, we'll pushState to
// update the URL in the browser.
async function navigate(pathname: string, push = false, popstateState: HistoryState | null = null) {
  let url = new URL(pathname, location.href);
  let basePath = url.pathname;
  let pathAnchor = url.hash.slice(1);
  let currentPath = location.pathname;
  let isSamePageAnchor = (!basePath || basePath === currentPath) && pathAnchor;

  // Save scroll position to current history entry before navigating away
  if (push) {
    saveScrollPosition();
  }

  if (isSamePageAnchor) {
    if (push) {
      history.pushState(null, '', pathname);
    }

    // Scroll to the anchor
    let element = document.getElementById(pathAnchor);
    if (element) {
      element.scrollIntoView();
    }
    return;
  }

  let rscPath = getRSCUrl(pathname);

  // Cancel any in-flight navigation
  if (currentAbortController) {
    currentAbortController.abort('Aborting due to new navigation');
  }

  // Create a new abort controller for this navigation
  const abortController = new AbortController();
  currentAbortController = abortController;
  const navigationId = ++currentNavigationId;

  const navigationPromise = (async () => {
    window.dispatchEvent(new CustomEvent('rsc-navigation-start'));

    // Use prefetched result if available, otherwise fetch
    const prefetchedPromise = getPrefetchedPromise(rscPath);
    const fetchPromise = prefetchedPromise ?? fetchRSC<ReactElement>(rscPath);

    try {
      let res = await fetchPromise;

      // Check if this navigation is still current before updating
      if (navigationId !== currentNavigationId) {
        // A newer navigation has started, ignore this result
        return;
      }

      // Check if this navigation was aborted
      if (abortController.signal.aborted) {
        return;
      }