Function onEvent

examples/pdf-server/server.ts:474–502

(eventType: string)

  };

  const onEvent = (eventType: string): void => {
    if (entry.debounce) clearTimeout(entry.debounce);
    entry.debounce = setTimeout(() => {
      entry.debounce = null;
      let s: fs.Stats;
      try {
        s = fs.statSync(resolved);
      } catch {
        return; // gone mid-atomic-write; next rename will re-attach
      }
      if (s.mtimeMs === entry.lastMtimeMs) return; // spurious / already sent
      entry.lastMtimeMs = s.mtimeMs;
      enqueueCommand(viewUUID, { type: "file_changed", mtimeMs: s.mtimeMs });
    }, FILE_WATCH_DEBOUNCE_MS);

    // Atomic saves replace the inode — old watcher stops firing. Re-attach.
    if (eventType === "rename") {
      try {
        entry.watcher.close();
      } catch {
        /* already closed */
      }
      try {
        entry.watcher = fs.watch(resolved, onEvent);
      } catch {
        // File removed, not replaced. Leave closed; pruneStaleQueues cleans up.
      }
    }
  };

  try {
    entry.watcher = fs.watch(resolved, onEvent);