Moment.js transform to date object

Moment.js transform to date object

Using Moment.js I can’t transform a correct moment object to a date object with timezones. I can’t get the correct date.
Example:
var oldDate = new Date(),
momentObj = moment(oldDate).tz(“MST7MDT”),
newDate = momentObj.toDate();
console.log(“start date ” + oldDate)
console.log(“Format from moment with offset ” + momentObj.format())
console.log(“Format from moment without offset ” + momentObj.utc().format())
console.log(“(Date object) Time with offset ” + newDate)
console.log(“(Date object) Time without offset “+ moment.utc(newDate).toDate())

Solutions/Answers:

Solution 1:

Use this to transform a moment object into a date object:

From http://momentjs.com/docs/#/displaying/as-javascript-date/

moment().toDate();

Yields:

Tue Nov 04 2014 14:04:01 GMT-0600 (CST)

Solution 2:

As long as you have initialized moment-timezone with the data for the zones you want, your code works as expected.

You are correctly converting the moment to the time zone, which is reflected in the second line of output from momentObj.format().

Switching to UTC doesn’t just drop the offset, it changes back to the UTC time zone. If you’re going to do that, you don’t need the original .tz() call at all. You could just do moment.utc().

Perhaps you are just trying to change the output format string? If so, just specify the parameters you want to the format method:

momentObj.format("YYYY-MM-DD HH:mm:ss")

Regarding the last to lines of your code – when you go back to a Date object using toDate(), you are giving up the behavior of moment.js and going back to JavaScript’s behavior. A JavaScript Date object will always be printed in the local time zone of the computer it’s running on. There’s nothing moment.js can do about that.

A couple of other little things:

  • While the moment constructor can take a Date, it is usually best to not use one. For “now”, don’t use moment(new Date()). Instead, just use moment(). Both will work but it’s unnecessarily redundant. If you are parsing from a string, pass that string directly into moment. Don’t try to parse it to a Date first. You will find moment’s parser to be much more reliable.

  • Time Zones like MST7MDT are there for backwards compatibility reasons. They stem from POSIX style time zones, and only a few of them are in the TZDB data. Unless absolutely necessary, you should use a key such as America/Denver.

Solution 3:

.toDate did not really work for me, So, Here is what i did :

futureStartAtDate = new Date(moment().locale("en").add(1, 'd').format("MMM DD, YYYY HH:MM"))

hope this helps

Solution 4:

Since momentjs has no control over javascript date object I found a work around to this.

const currentTime = new Date();    
const convertTime = moment(currentTime).tz(timezone).format("YYYY-MM-DD HH:mm:ss");
const convertTimeObject = new Date(convertTime);

This will give you a javascript date object with the converted time

Solution 5:

I needed to have timezone information in my date string. I was originally using moment.tz(dateStr, 'America/New_York').toString(); but then I started getting errors about feeding that string back into moment.

I tried the moment.tz(dateStr, 'America/New_York').toDate(); but then I lost timezone information which I needed.

The only solution that returned a usable date string with timezone that could be fed back into moment was moment.tz(dateStr, 'America/New_York').format();

Solution 6:

moment has updated the js lib as of 06/2018.

var newYork    = moment.tz("2014-06-01 12:00", "America/New_York");
var losAngeles = newYork.clone().tz("America/Los_Angeles");
var london     = newYork.clone().tz("Europe/London");

newYork.format();    // 2014-06-01T12:00:00-04:00
losAngeles.format(); // 2014-06-01T09:00:00-07:00
london.format();     // 2014-06-01T17:00:00+01:00

if you have freedom to use Angular5+, then better use datePipe feature there than the timezone function here. I have to use moment.js because my project limits to Angular2 only.