in src/Transition.js [194:207]
getTimeouts() {
const { timeout } = this.props;
let exit, enter, appear;
exit = enter = appear = timeout;
if (timeout != null && typeof timeout !== 'number') {
exit = timeout.exit;
enter = timeout.enter;
// TODO: remove fallback for next major
appear = timeout.appear !== undefined ? timeout.appear : enter;
}
return { exit, enter, appear };
}