Format Date in JavaScript

Create a Date

In Javascript, you can use the new Date() constructor to create a new Date object.

let now = new Date() // current date and time
let date1 = new Date(1700320703000); // passing milliseconds epoch timestamp
let date2 = new Date(2023, 11, 18, 3, 24, 0); //year, monthIndex, day, hours, minutes, seconds (the month is 0-indexed)
let date3 = new Date("2023-11-18T03:24:00")
var date4 = new Date("2023-11-18T03:24:00.000+08:00"); //YYYY-MM-DDTHH:mm:ss.sssZ

Get Current Unixt timestamp

let timestamp1 = new Date().getTime() //UNIX epoch timestamp in milliseconds
let timestamp2 = Math.round(new Date().getTime() / 1000) //UNIX epoch timestamp in seconds

toString()

let now = new Date()
console.log(now.toString()) //Fri Nov 17 2023 16:02:55 GMT+0800 (China Standard Time)

toDateString()

let now = new Date()
console.log(now.toDateString()) //Fri Nov 17 2023

toLocaleString()

toLocaleString(locales, options)

let now = new Date()
console.log(now.toLocaleString()) // 11/17/2023, 4:02:55 PM
console.log(now.toLocaleString('en-US')) // 11/17/2023, 4:02:55 PM
console.log(now.toLocaleString('en-US',{ timeZone: 'US/Pacific' })) // 11/17/2023, 12:02:55 AM
console.log(now.toLocaleString('zh-CN')) // 2023/11/17 16:02:55
console.log(now.toLocaleString('zh-CN',{ timeZone: 'UTC' })) // 2023/11/17 08:02:55

ToLocaleDateString()

let now = new Date()
const options = {
  weekday: 'long',
  year: 'numeric',
  month: 'long',
  day: 'numeric',
};
console.log(now.toLocaleDateString()) // 11/17/2023
console.log(now.toLocaleDateString('en-US')) // 11/17/2023
console.log(now.toLocaleDateString('en-US',options)) // Friday, November 17, 2023
console.log(now.toLocaleDateString('zh-CN')) // 2023/11/17
console.log(now.toLocaleDateString('zh-CN',options)) // 2023年11月17日星期五

ToLocaleTimeString()

let now = new Date()
console.log(now.toLocaleTimeString()) // 4:02:55 PM
console.log(now.toLocaleTimeString('en-US')) // 4:02:55 PM
console.log(now.toLocaleTimeString('zh-CN')) // 16:02:55

toUTCString()

let now = new Date()
console.log(now.toUTCString()) //Fri, 17 Nov 2023 08:02:55 GMT

toISOString()

Format a date as an ISO 8601 format. The timezone is always UTC, as denoted by the suffix Z.

let now = new Date()
console.log(now.toISOString()) //2023-11-17T08:02:55.274Z

RFC3339 Format

Format a date as an RFC 3339 format with timezone.

function rfc3339(d) {
    
    function pad(n) {
        return n < 10 ? "0" + n : n;
    }

    function timezoneOffset(offset) {
        var sign;
        if (offset === 0) {
            return "Z";
        }
        sign = (offset > 0) ? "-" : "+";
        offset = Math.abs(offset);
        return sign + pad(Math.floor(offset / 60)) + ":" + pad(offset % 60);
    }

    return d.getFullYear() + "-" +
        pad(d.getMonth() + 1) + "-" +
        pad(d.getDate()) + "T" +
        pad(d.getHours()) + ":" +
        pad(d.getMinutes()) + ":" +
        pad(d.getSeconds()) + 
        timezoneOffset(d.getTimezoneOffset());
}

const now = new Date();
console.log(rfc3339(now)) // 2023-11-21T15:55:12+08:00

Get Current time zone and supported time zone list

const now = new Date();
console.log(now.getTimezoneOffset()) // -480
console.log(Intl.DateTimeFormat().resolvedOptions().timeZone) //Asia/Shanghai
console.log(Intl.supportedValuesOf('timeZone')); //Get timezones list

Format Date to another timezone

JavaScript Date object does not store any timezone information (it contains unix timestamp inside, and when you call .getMinutes (), getHours (), toString () it uses system timezone). So if you want to format a Date to another timezone, you need to use moment-timezone.

const moment = require('moment-timezone');
const now = new Date()
console.log(now.toString()) //default timezone: Wed Nov 22 2023 12:13:10 GMT+0800 (China Standard Time)
console.log(moment(now).toString()) //default timezone: Wed Nov 22 2023 12:13:10 GMT+0800
console.log(moment(now).tz("America/New_York").toString()) //New York Timezone: Tue Nov 21 2023 23:13:10 GMT-0500
console.log(moment(now).tz("America/New_York").toDate().toString()) //Convert to Date Object, use default timezone: Wed Nov 22 2023 12:13:10 GMT+0800 (China Standard Time)

Get User Locale

const locale = (navigator && navigator.language) || "en"; 
console.log(locale); // en-US

Parameters

locales

locale	Meaning
ar-SA	Arabic (Saudi Arabia)
ar-SA	Arabic (Saudi Arabia)
bn-BD	Bangla (Bangladesh)
bn-IN	Bangla (India)
cs-CZ	Czech (Czech Republic)
da-DK	Danish (Denmark)
de-AT	Austrian German
de-CH	"Swiss" German
de-DE	Standard German (as spoken in Germany)
el-GR	Modern Greek
en-AU	Australian English
en-CA	Canadian English
en-GB	British English
en-IE	Irish English
en-IN	Indian English
en-NZ	New Zealand English
en-US	US English
en-ZA	English (South Africa)
es-AR	Argentine Spanish
es-CL	Chilean Spanish
es-CO	Colombian Spanish
es-ES	Castilian Spanish (as spoken in Central-Northern Spain)
es-MX	Mexican Spanish
es-US	American Spanish
fa-IR	Iranian (Iran)
fi-FI	Finnish (Finland)
fr-BE	Belgian French
fr-CA	Canadian French
fr-CH	"Swiss" French
fr-FR	Standard French (especially in France)
he-IL	Hebrew (Israel)
hi-IN	Hindi (India)
hu-HU	Hungarian (Hungary)
id-ID	Indonesian (Indonesia)
it-CH	"Swiss" Italian
it-IT	Standard Italian (as spoken in Italy)
ja-JP	Japanese (Japan)
ko-KR	Korean (Republic of Korea)
nl-BE	Belgian Dutch
nl-NL	Standard Dutch (as spoken in The Netherlands)
no-NO	Norwegian (Norway)
pl-PL	Polish (Poland)
pt-BR	Brazilian Portuguese
pt-PT	European Portuguese (as written and spoken in Portugal)
ro-RO	Romanian (Romania)
ru-RU	Russian (Russian Federation)
sk-SK	Slovak (Slovakia)
sv-SE	Swedish (Sweden)
ta-IN	Indian Tamil
ta-LK	Sri Lankan Tamil
th-TH	Thai (Thailand)
tr-TR	Turkish (Turkey)
zh-CN	Mainland China, simplified characters
zh-HK	Hong Kong, traditional characters
zh-TW	Taiwan, traditional characters

options

key	options
dateStyle	"full","long","medium","short"
timeStyle	"full","long","medium","short"
localeMatcher	"best-fit" (default), "lookup"
timeZone
hour12	false,true
hourCycle	"h11","h12","h23","h24"
formatMatcher	"basic","best-fit" (default)
weekday	"long","short","narrow"
year	"2-digit","numeric"
month	"2-digit","long","narrow","numeric","short"
day	"2-digit","numeric",hour "2-digit","numeric"
minute	"2-digit","numeric"
second	"2-digit","numeric"
timeZoneName	"long","short"