Moment.js，Moment-timezone：在东部时区输入和显示？

Question

I've got a javascript app that the user insists that regardless of location of the app user, they want date/times entered by the user in Eastern time. That they will be sent to the database and stored, and later displayed again in the app and displayed in Eastern timezone. So I was looking to use moment.js and moment-timezone, but can't figure out how to make it work. When I try const objMoment = moment(), objMoment appears to contain a time offset from the current time. I was wanting to get a moment object that is whatever time, and then objMoment.tz("America/New_York") but I ended up with a time that is 5 hours off from what it should be.

        const objMoment = moment();
        const objEastern = objMoment.clone().tz("America/New_York");
        debugger;
          formData.SwoDate = objMoment.toDate();
        debugger;

Answer 1

A few things:

• You don't need to create a local moment and clone it. You can instead construct a moment directly in a specific time zone with:

   moment.tz('America/New_York')

• Since you call toDate() , the result is always going to be a Date object that represents "now". It doesn't matter if that comes from a Moment that's been set to a different time zone or not. It's the same moment in time.

   moment().valueOf() // 1600198416842 moment.utc().valueOf() // 1600198416842 moment.tz('America/New_York').valueOf() // 1600198416842 new Date().valueOf() // 1600198416842 Date.now() // 1600198416842

• If you want to see the time in a different time zone, you would need to use a function like format instead.

   moment.utc().format() // "2020-09-15T19:33:36Z" moment.tz('America/New_York').format() // "2020-09-15T15:33:36-04:00"

• Moment is a legacy library. You should probably choose a different library, or perhaps no library at all. Please read: Moment Project Status