feat: notify document updates over websocket

apps/server/internal/httpserver/static/realtime.js

@@ -0,0 +1,35 @@
+(function () {
+  const notice = document.querySelector("[data-version-notice]");
+  const reload = document.querySelector("[data-version-reload]");
+  const documentShell = document.querySelector("[data-document-path][data-document-hash]");
+
+  if (!notice || !reload || !documentShell || !window.WebSocket) {
+    return;
+  }
+
+  const currentPath = documentShell.getAttribute("data-document-path");
+  const currentHash = documentShell.getAttribute("data-document-hash");
+  const protocol = window.location.protocol === "https:" ? "wss:" : "ws:";
+  const socket = new WebSocket(protocol + "//" + window.location.host + "/ws");
+
+  socket.addEventListener("message", function (event) {
+    let payload;
+    try {
+      payload = JSON.parse(event.data);
+    } catch {
+      return;
+    }
+
+    if (payload.type !== "document_version" || !payload.data) {
+      return;
+    }
+
+    if (payload.data.path === currentPath && payload.data.hash !== currentHash) {
+      notice.hidden = false;
+    }
+  });
+
+  reload.addEventListener("click", function () {
+    window.location.reload();
+  });
+})();