function warnOnce(msg) {
  var hasWarned = false;
  return function () {
    if (!hasWarned) {
      console.warn(msg);
      hasWarned = true;
    }
  };
}
React Flip Move | enterLeavePresets
(c) 2016-present Joshua Comeau

This contains the master list of presets available for enter/leave animations,
along with the mapping between preset and styles.