useImperativeHandle.tsx

export interface MyInputHandles {
  focus(): void;
}

const MyInput: RefForwardingComponent<MyInputHandles, MyInputProps> = (
  props,
  ref
) => {
  const inputRef = useRef<HTMLInputElement>(null);

  useImperativeHandle(ref, () => ({
    focus: () => {
      if (inputRef.current) {
        inputRef.current.focus();
      }
    },
  }));

  return <input {...props} ref={inputRef} />;
};

export default forwardRef(MyInput);