Function MessageBranch

web/src/components/ai-elements/message.tsx:144–193

({
  defaultBranch = 0,
  onBranchChange,
  className,
  ...props
}: MessageBranchProps)

};

export const MessageBranch = ({
  defaultBranch = 0,
  onBranchChange,
  className,
  ...props
}: MessageBranchProps) => {
  const [currentBranch, setCurrentBranch] = useState(defaultBranch);
  const [branches, setBranches] = useState<ReactElement[]>([]);

  const handleBranchChange = useCallback(
    (newBranch: number) => {
      setCurrentBranch(newBranch);
      onBranchChange?.(newBranch);
    },
    [onBranchChange],
  );

  const goToPrevious = useCallback(() => {
    const newBranch =
      currentBranch > 0 ? currentBranch - 1 : branches.length - 1;
    handleBranchChange(newBranch);
  }, [currentBranch, branches.length, handleBranchChange]);

  const goToNext = useCallback(() => {
    const newBranch =
      currentBranch < branches.length - 1 ? currentBranch + 1 : 0;
    handleBranchChange(newBranch);
  }, [currentBranch, branches.length, handleBranchChange]);

  const contextValue = useMemo<MessageBranchContextType>(
    () => ({
      branches,
      currentBranch,
      goToNext,
      goToPrevious,
      setBranches,
      totalBranches: branches.length,
    }),
    [branches, currentBranch, goToNext, goToPrevious],
  );

  return (
    <MessageBranchContext.Provider value={contextValue}>
      <div
        className={cn("grid w-full gap-2 [&>div]:pb-0", className)}
        {...props}
      />
    </MessageBranchContext.Provider>
  );
};

export type MessageBranchContentProps = HTMLAttributes<HTMLDivElement>;