fix: #2252 polyfill composing for old safari browsers

app/components/chat.tsx

@@ -172,10 +172,29 @@ function PromptToast(props: {
 function useSubmitHandler() {
   const config = useAppConfig();
   const submitKey = config.submitKey;
+  const isComposing = useRef(false);
+
+  useEffect(() => {
+    const onCompositionStart = () => {
+      isComposing.current = true;
+    };
+    const onCompositionEnd = () => {
+      isComposing.current = false;
+    };
+
+    window.addEventListener("compositionstart", onCompositionStart);
+    window.addEventListener("compositionend", onCompositionEnd);
+
+    return () => {
+      window.removeEventListener("compositionstart", onCompositionStart);
+      window.removeEventListener("compositionend", onCompositionEnd);
+    };
+  }, []);
 
   const shouldSubmit = (e: React.KeyboardEvent<HTMLTextAreaElement>) => {
     if (e.key !== "Enter") return false;
-    if (e.key === "Enter" && e.nativeEvent.isComposing) return false;
+    if (e.key === "Enter" && (e.nativeEvent.isComposing || isComposing.current))
+      return false;
     return (
       (config.submitKey === SubmitKey.AltEnter && e.altKey) ||
       (config.submitKey === SubmitKey.CtrlEnter && e.ctrlKey) ||