message: workaround Locale not exported
diff: @@ -27,6 +27,10 @@ import * as startOfWeek from 'date-fns/startOfWeek';
  import * as startOfYear from 'date-fns/startOfYear';
  import { Utils } from '../typings/utils';
  +// Locale is not exported from date-fns, so we need to workaround that https://github.com/date-fns/date-fns/issues/932
  +import * as SampleLocale from 'date-fns/locale/en-US';
  +type Locale = typeof SampleLocale;
  +
  export default class DateFnsUtils implements Utils<Date> {
  public locale?: Locale;
  