CSSTransition을 사용하면 팝업에서 Transition 효과를 적용 할수 있습니다. https://reactcommunity.org/react-transition-group/transition React Transition Group A function child can be used instead of a React element. This function is called with the current transition status ('entering', 'entered', 'exiting', 'exited'), which can be used to apply context specific props to a component.
{state => ( )} reactcommunity.org .....
원문 링크 : React Transition Modal 적용
