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Currently, I am converting the UTC time to a time of a specific timezone using Moment.js in my backend. It allows me to convert 2021-01-04T01:20:00Z to 2021-01-03T20:20:00-05:00 for America/toronto timezone.

I am wondering if I can achieve this conversion with JS without a module such as Moment.js?

gshow8 shac
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  • You could use [toLocaleString](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleString) – Alfred Jan 06 '21 at 04:13
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    Does this answer your question? [How to initialize a JavaScript Date to a particular time zone](https://stackoverflow.com/questions/15141762/how-to-initialize-a-javascript-date-to-a-particular-time-zone) – user202729 Jan 06 '21 at 04:13

2 Answers2

2
new Date('2021-01-04T01:20:00Z').toLocaleString('en-US', {timeZone: 'America/Toronto'})

"1/3/2021, 8:20:00 PM"

options = {
  year: 'numeric', month: 'numeric', day: 'numeric',
  hour: 'numeric', minute: 'numeric', second: 'numeric',
  hour12: false,
  timeZone: 'America/Toronto'
};
new Date('2021-01-04T01:20:00Z').toLocaleString('en-US', options)

or

new Intl.DateTimeFormat('en-US', options).format(new Date('2021-01-04T01:20:00Z'))

"1/3/2021, 20:20:00"

options = {
  year: 'numeric', month: 'numeric', day: 'numeric',
  hour: 'numeric', minute: 'numeric', second: 'numeric',
  hour12: false,
  timeZone: 'America/Toronto',
  timeZoneName: 'short'
};
new Intl.DateTimeFormat('en-US', options).format(new Date('2021-01-04T01:20:00Z'))

"1/3/2021, 20:20:00 EST"

slacker
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1

Here's a solution that is very re-usable.

//Adds the toIsoString() function to the date object
Date.prototype.toIsoString = function() {
    var tzo = -this.getTimezoneOffset(),
        dif = tzo >= 0 ? '+' : '-',
        pad = function(num) {
            var norm = Math.floor(Math.abs(num));
            return (norm < 10 ? '0' : '') + norm;
        };
    return this.getFullYear() +
        '-' + pad(this.getMonth() + 1) +
        '-' + pad(this.getDate()) +
        'T' + pad(this.getHours()) +
        ':' + pad(this.getMinutes()) +
        ':' + pad(this.getSeconds()) +
        dif + pad(tzo / 60) +
        ':' + pad(tzo % 60);
}

//Creates a date object with the utc supplied, which automatically gets translated to your timezone
var localISOTime = new Date('2021-01-04T01:20:00Z');

//Outputs the date in ISO format with the timezone extension
console.log(localISOTime.toIsoString());
GreenCobalt
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