moment.tz is giving incorrect result

问题:

I was trying to convert dates according to selected timezone. I was surprised to see same result for dates with 5 mins of time difference. For ex,

var x = "2017-07-10T18:30:00.000Z"
var y = "2017-07-10T18:35:00.000Z"
var z = "2017-07-10T18:45:00.000Z"

and tried converting them to using moment.tz:

moment.tz(x, 'America/New_York').format('DD/MM/YYYY HH:MM:SS');
moment.tz(y, 'America/New_York').format('DD/MM/YYYY HH:MM:SS')
moment.tz(z, 'America/New_York').format('DD/MM/YYYY HH:MM:SS')

To my surprise, result was same for all 3 being "10/07/2017 14:07:00". What's going wrong? Any help will be appreciated.

回答1:

Short answer:

The issue is that you are using uppercase MM (month) instead of lowercase mm minutes in you format(). Note that, you have the same problem for SS (fractional seconds) and ss (seconds).

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General note about you code sample:

Use moment.tz for parsing time string using a given timezone (e.g. 'America/New_York'), moment.tz is not made for converting input to given timezone.

You have to use tz() method to convert a moment object to a given timezone.

Note that your input string ends with Z so it represents time in UTC.

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As Matt Johnson pointed out in comments, in your case even moment.tz(input, zone) would convert input to given zone because input string contains the Z (that stays for UTC timezone). Anyway this kind of approach is discouraged.

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Here a code sample that parses UTC time string and converts it to 'America/New_York' timezone:

var x = "2017-07-10T18:30:00.000Z";
var y = "2017-07-10T18:35:00.000Z";
var z = "2017-07-10T18:45:00.000Z";

console.log( moment.utc(x).tz('America/New_York').format('DD/MM/YYYY HH:MM:SS') );
console.log( moment.utc(y).tz( 'America/New_York').format('DD/MM/YYYY HH:mm:ss') );
console.log( moment.utc(z).tz( 'America/New_York').format('DD/MM/YYYY HH:mm:ss') );

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.18.1/moment.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment-timezone/0.5.13/moment-timezone-with-data-2012-2022.min.js"></script>