A plugin of relativeTimeFormat.
new RelativeTIime({lang: 'en', date:'2019-7-17 17:00:00'}).output // "1 hour ago"
new RelativeTIime({lang: 'zh', date:'2019-7-16 17:00:00'}).output // "昨天"
new RelativeTIime({lang: 'zh', date:'2019-7-15 17:00:00'}).output // "前天"
default
is ‘en’
support ` Date object,
milliseconds (Number), time in
2019-10-1 10:00:00` format.