获取本月的第一天和最后一天

Question

this has been answered here however maybe something has changed as that no longer works.

 function firstAndLast() { const startDate = new Date(2020, 8, 1); const endDate = new Date(2020, startDate.getMonth() + 1, 0) console.log('startDate', startDate) // <-- 2020-08-31T22:00:00.000Z console.log('endDate', endDate) // <-- 2020-09-29T22:00:00.000Z } firstAndLast();

as the docs say the parameters are new Date(YYYY, MM, DD, hh, mm, ss, ms)

I am entering the year 2020 the month august (note this is node not browser) and day 1 the first of the month. What is going on here?

Answer 1

You have to consider the Timezone offset. https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Objets_globaux/Date/getTimezoneOffset

 function firstAndLast() { const offset = new Date().getTimezoneOffset() / 60 const startDate = new Date(2020, 8, 1, 0-offset); const endDate = new Date(2020, startDate.getMonth() + 1, 0, 0-offset) console.log('startDate', startDate) // <-- 2020-08-31T22:00:00.000Z console.log('endDate', endDate) // <-- 2020-09-29T22:00:00.000Z } firstAndLast();