一旦你有了 Day.js 对象，你可能想以某种方式操作它。 ¥Once you have a Day.js object, you may want to manipulate it in some way. Day.js 支持这样的方法链： ¥Day.js supports method chaining like this: dayjs('2019-01-25').add(1, 'day').subtract(1, 'year').year(2009).toString()
