Fetch scrollback messages earlier, add them when ready

client/src/js/middleware/message.js

@@ -0,0 +1,35 @@
+import * as actions from '../state/actions';
+
+//
+// This middleware handles waiting until MessageBox
+// is ready before adding messages to the top
+//
+const message = store => next => {
+  const ready = {};
+  const cache = {};
+
+  return action => {
+    if (action.type === actions.ADD_MESSAGES && action.prepend) {
+      const key = `${action.server} ${action.channel}`;
+
+      if (ready[key]) {
+        ready[key] = false;
+        return next(action);
+      }
+
+      cache[key] = action;
+    } else if (action.type === actions.ADD_FETCHED_MESSAGES) {
+      const key = `${action.server} ${action.channel}`;
+      ready[key] = true;
+
+      if (cache[key]) {
+        store.dispatch(cache[key]);
+        cache[key] = undefined;
+      }
+    } else {
+      return next(action);
+    }
+  };
+};
+
+export default message;