Convert TimeZone Time string correctly into Local Time

Question

I am trying to convert a time string returned from our backend system but I am unable to get the correct local time.

Time string returned from backend: "2020-08-28T07:00:00.000Z"

Expected local time needed: Aug 28, 2020 12:00 AM

I tried:

converting it with Moment.js Failed:
```
    moment(backendTime).format(
     "MMM D,YYYY h:mm a"
  ) 
```
Somehow I got "Jan 1st 20 12:00 AM", I don't understand it at all
converting it by casting to Date Failed as well:

  Date("2020-08-28T07:00:00.000Z")

Ended up getting: " Mon Sep 21 2020 00:07:29 GMT-0700 (Pacific Daylight Time) "

I am running out of ideas right now, I feel it shouldn't be this difficult but just cannot get it.

@AlwaysHelping I am in Pacific Time, is the timezone the cause of not getting it translated to the correct time ? — Edward Sun, Sep 21 '20 at 07:20
you can change date format by using this also: - console.log(format(new Date(), 'yyyy/MM/dd kk:mm:ss')) — bharti parmar, Sep 21 '20 at 07:28

Cninroh · Answer 1 · 2020-09-21T07:41:30.707

0

The format you are getting is exactly what you have requested.

To get the output you desire using moment.js you need to use the following format:

moment(backendTime).format("MMM DD, YYYY hh:mm A");

You can test it here: https://jsfiddle.net/oz6mx3nh/

edited Sep 21 '20 at 07:41

answered Sep 21 '20 at 07:21

Cninroh

1,796
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Reyno · Answer 2 · 2020-09-21T08:14:40.620

In vanilla JS you can use the DateTimeFormat to format your dates based on a timezone. All the options for DateTimeFormat are documented here.

The different options for the locale (en-US) is listed here

Here is a full list of all the time zones.

See bottom snippet for the output of each locale (in the provided list)

const date = new Date("2020-08-28T07:00:00.000Z");

const format = new Intl.DateTimeFormat(
  "en-US",
  {
    month: "short",
    day: "2-digit",
    year: "numeric",
    hour: "2-digit",
    hour12: true,
    minute: "2-digit",
    timeZone: "America/New_York",
  }
).format(date)

console.log(format);

A list of outputs from every locale:

const date = new Date("2020-08-28T07:00:00.000Z");

const locales = ["ar-SA", "bn-BD", "bn-IN", "cs-CZ", "da-DK", "de-AT", "de-CH", "de-DE", "el-GR", "en-AU", "en-CA", "en-GB", "en-IE", "en-IN", "en-NZ", "en-US", "en-ZA", "es-AR", "es-CL", "es-CO", "es-ES", "es-MX", "es-US", "fi-FI", "fr-BE", "fr-CA", "fr-CH", "fr-FR", "he-IL", "hi-IN", "hu-HU", "id-ID", "it-CH", "it-IT", "jp-JP", "ko-KR", "nl-BE", "nl-NL", "no-NO", "pl-PL", "pt-BR", "pt-PT", "ro-RO", "ru-RU", "sk-SK", "sv-SE", "ta-IN", "ta-LK", "th-TH", "tr-TR", "zh-CN", "zh-HK", "zh-TW"];

const formatDate = (locale, date) => new Intl.DateTimeFormat(
  locale,
  {
    month: "short",
    day: "2-digit",
    year: "numeric",
    hour: "2-digit",
    hour12: true,
    minute: "2-digit",
    timeZone: "America/New_York",
  }
).format(date);

// Loop over each locale
for(const locale of locales) {
  const formatted = formatDate(locale, date);
  
  console.log(`${locale}: ${formatted}`);
}

score 0 · Answer 3 · answered Sep 21 '20 at 16:45

A few things:

Assuming your computer is set for Pacific time, then:
```
moment("2020-08-28T07:00:00.000Z").format("MMM D, YYYY h:mm a")
//=> "Aug 28, 2020 12:00 am"
```
That will indeed return the value you expected. You said you got "Jan 1st 20 12:00 AM", but that is not possible, as neither the values nor the format matches.
When you tried the Date object, you got the result you did because you omitted the new keyword (see this explanation). It should instead be:
```
new Date("2020-08-28T07:00:00.000Z")
```
Keep in mind that this produces a Date object. If you log that object directly, the result is implementation specific. It may vary across browsers. Instead, you should call a function such as toString or toLocaleString from it.
If this is a new project, you should probably avoid using Moment. Please read https://momentjs.com/docs/#/-project-status/

Convert TimeZone Time string correctly into Local Time

3 Answers3