Sample JavaScript code of React Transition Group's SwitchTransition component

react-transition-group-switch.js

const App = () => {
  const [state, setState] = React.useState(true);
  return (
    <>
      <div className="main">
        <SwitchTransition mode={'in-out'}>
          <CSSTransition
            key={state}
            addEndListener={(node, done) => {
              node.addEventListener("transitionend", done, false);
            }}
            classNames="fade"
          >
            <div className="button-container">
              <Button onClick={() => setState(!state)}>
                {state ? "Hello, world!" : "Goodbye, world!"}
              </Button>
            </div>
          </CSSTransition>
        </SwitchTransition>
      </div>
    </>
  );
}