moment-timezone parsing the given time zone

Question

I have an issue when parsing the Date object using the moment-timezone

The problem

I am creating a nodejs app that should check the new Date() object with arbitrary time from database (and act accordingly). The time, and the timezone are persisted in database.

In example

time | timezone
11:00| US/Eastern

When a REST call comes, I have to take new Date() object and to transform it to given timezone and see whether the current time is later than 9am. But servers timezone and persisted timezone are not the same.

The issue

I create todays date string like this

function getTodaysDate() {
    var today = new Date(),
        dd = today.getDate(),
        mm = today.getMonth()+1,
        yyyy = today.getFullYear();

    if(dd<10) {
        dd='0'+dd
    }

    if(mm<10) {
        mm='0'+mm
    }
    
    return yyyy +'-' + mm + '-' + dd;
    
}

And trying to create Timestamp object with moment-timezone

startTime = moment.tz(new Date(getTodaysDate() + ' ' + '11:00'), 'US/Eastern');

But the framework correctly takes the date and transforms it to US/Eastern time zone.

So when I print startTime.format();

I get

2016-08-01T07:00:00-04:00

And I would like

2016-08-01T11:00:00-04:00

So is there a way using moment-timezone package to set the Date and time and to just treat them as given timezone?

Answer 1

So the problem was that

startTime = moment.tz('here the date goes', 'US/Eastern');

Was either expecting ISO format or manually formatted (syntax of this was not known to me), or the Date() object. I first tried with this

2016-08-01 11:00 

Moment library complained (I will post the full error message when I come to office).

Solution

Add T.

startTime = moment.tz('2016-08-01T11:00', 'US/Eastern');

I hate timedate libraries and how we track of time.

Answer 2

You don't need any of the Date object manipulation. In theory, you should just be able to do:

var zone = 'US/Eastern'
var time = '11:00'

var result = moment.tz(time, 'HH:mm', zone).format();

However, there's a known bug with this that uses the UTC current date instead of the time zone's current date. Until it's fixed, you have to do this instead:

var zone = 'US/Eastern'
var time = '11:00'

var s = moment.tz(zone).format('YYYY-MM-DD') + ' ' + time;
var m = moment.tz(s, zone);
var result = m.format();

(this assumes your input time value is in HH:mm format)