fix(MessageBar): Fix IME language handling

Languages that rely on IME keyboards may use the enter key for final text selection on Mac. The MessageBar also uses enter key for submit. The result was that IME input, such as Japanese, was prematurely submitted. I added an additional check for whether the onCompositionEnd event is complete and also added some additional handling for Safari, which is a little bit of a special case. This should resolve the issue on Mac. I manually checked Edge, Chrome, Safari, and Firefox on my machine with a Japanese keyboard.

Assisted-by: Cursor (used to generate boilerplate for handleCompositionStart/End, etc.)

Author: rebeccaalpert

packages/module/src/MessageBar/MessageBar.tsx

@@ -141,6 +141,7 @@ export const MessageBarBase: FunctionComponent<MessageBarProps> = ({
   const [message, setMessage] = useState<string | number>(value ?? '');
   const [isListeningMessage, setIsListeningMessage] = useState<boolean>(false);
   const [hasSentMessage, setHasSentMessage] = useState(false);
+  const [isComposing, setIsComposing] = useState(false);
   const inputRef = useRef<HTMLTextAreaElement>(null);
   const textareaRef = (innerRef as React.RefObject<HTMLTextAreaElement>) ?? inputRef;
   const attachButtonRef = useRef<HTMLButtonElement>(null);
@@ -285,21 +286,38 @@ export const MessageBarBase: FunctionComponent<MessageBarProps> = ({
 
   const handleKeyDown = useCallback(
     (event: ReactKeyboardEvent) => {
-      if (event.key === 'Enter' && !event.shiftKey) {
+      // Japanese and other languages may use IME for character input.
+      // In these cases, enter is used to select the final input, so we need to check for composition end instead.
+      // See more info at https://www.stum.de/2016/06/24/handling-ime-events-in-javascript/
+      // Chrome, Edge, and Firefox seem to work well with just the compose event.
+      // Safari is a little bit special. We need to handle 229 as well in this case.
+      const nativeEvent = event.nativeEvent as KeyboardEvent;
+      const isCompositionKey = nativeEvent.which === 229;
+      const isCurrentlyComposing = isComposing || isCompositionKey;
+
+      if (event.key === 'Enter' && !isCurrentlyComposing && !event.shiftKey) {
         event.preventDefault();
         if (!isSendButtonDisabled && !hasStopButton) {
           handleSend(message);
         }
       }
-      if (event.key === 'Enter' && event.shiftKey) {
+      if (event.key === 'Enter' && !isCurrentlyComposing && event.shiftKey) {
         if (textareaRef.current) {
           handleNewLine(textareaRef.current);
         }
       }
     },
-    [isSendButtonDisabled, hasStopButton, handleSend, message]
+    [isSendButtonDisabled, hasStopButton, handleSend, message, isComposing]
   );
 
+  const handleCompositionStart = useCallback(() => {
+    setIsComposing(true);
+  }, []);
+
+  const handleCompositionEnd = useCallback(() => {
+    setIsComposing(false);
+  }, []);
+
   const handleAttachMenuToggle = () => {
     attachMenuProps?.setIsAttachMenuOpen && attachMenuProps?.setIsAttachMenuOpen(!attachMenuProps?.isAttachMenuOpen);
     attachMenuProps?.onAttachMenuToggleClick();
@@ -402,6 +420,8 @@ export const MessageBarBase: FunctionComponent<MessageBarProps> = ({
           placeholder={isListeningMessage ? listeningText : placeholder}
           ref={textareaRef}
           onKeyDown={handleKeyDown}
+          onCompositionStart={handleCompositionStart}
+          onCompositionEnd={handleCompositionEnd}
           {...props}
         />
       </div>