Add streaming chat

app/javascript/controllers/chat_controller.js

@@ -0,0 +1,32 @@
+import { Controller } from "@hotwired/stimulus";
+
+// Connects to data-controller="chat-scroll"
+export default class extends Controller {
+  static targets = ["form", "messages"];
+
+  connect() {
+    this.scrollToBottom();
+
+    this.observer = new MutationObserver(() => {
+      this.scrollToBottom();
+      this.clearInput();
+    });
+
+    this.observer.observe(this.messagesTarget, {
+      childList: true,
+      subtree: true,
+    });
+  }
+
+  disconnect() {
+    this.observer.disconnect();
+  }
+
+  scrollToBottom() {
+    this.messagesTarget.scrollTop = this.messagesTarget.scrollHeight;
+  }
+
+  clearInput() {
+    this.formTarget.querySelector("textarea").value = "";
+  }
+}