shlink-web-client/src/utils/helpers/date.ts

import * as moment from 'moment';

type MomentOrString = moment.Moment | string;
type NullableDate = MomentOrString | null;

const isMomentObject = (date: moment.Moment | string): date is moment.Moment => typeof (date as moment.Moment).format === 'function';

const formatDateFromFormat = (date?: NullableDate, format?: string): NullableDate | undefined =>
  !date || !isMomentObject(date) ? date : date.format(format);

export const formatDate = (format = 'YYYY-MM-DD') => (date?: NullableDate) => formatDateFromFormat(date, format);

export const formatIsoDate = (date: NullableDate) => formatDateFromFormat(date, undefined);