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Dates

Creating a date

// current date/time
let today = new Date();

// specific date
let birthday = new Date('December 17, 1995 03:24:00');
let birthday = new Date('1995-12-17T03:24:00');

// the month is 0-indexed
let birthday = new Date(1995, 11, 17)
let birthday = new Date(1995, 11, 17, 3, 24, 0)

// passing epoch timestamp
let birthday = new Date(628021800000)

Deconstructing Date Object

const date = new Date();

const [month, day, year] = [date.getMonth(), date.getDate(), date.getFullYear()];

const [hour, minutes, seconds] = [date.getHours(), date.getMinutes(), date.getSeconds()];

Variations

new Date()
new Date(value)
new Date(dateString)
new Date(dateObject)

new Date(year, monthIndex)
new Date(year, monthIndex, day)
new Date(year, monthIndex, day, hours)
new Date(year, monthIndex, day, hours, minutes)
new Date(year, monthIndex, day, hours, minutes, seconds)
new Date(year, monthIndex, day, hours, minutes, seconds, milliseconds)

Methods

getDay()

var Xmas95 = new Date('December 25, 1995 23:15:30');

// returns day of the week for the specified date according to local time, where 0 represents Sunday
var weekday = Xmas95.getDay();
console.log(weekday); // 1

// returns the day of the month for the specified date according to local time
const day = Xmas95.getDate();
console.log(day); // 25

Time-zone specific conversions

Date.toLocaleTimeString()

Returns a string presenting the time portion of given Date instance according to language-specific conventions

// syntax
toLocaleTimeString()
toLocaleTimeString(locales)
toLocaleTimeString(locales, options)

// creating date
const event = new Date('August 19, 1975 23:15:30 GMT+00:00');

// US locale
console.log(event.toLocaleTimeString('en-US')); // 1:15:30 AM
// Italian locale
console.log(event.toLocaleTimeString('it-IT')); // 01:15:30

Options Parameter

// creating a date
const date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));

// defining options
const options = { timeZone: "UTC", timeZoneName: "short" };

console.log(date.toLocaleTimeString("en-US", options));
// "3:00:00 AM GMT"

// creating time with specific zone
new Date().toLocaleString("en-US", {timeZone: "America/New_York"})

// other time zones
const world_timezones =
[
  'Europe/Andorra',
  'Asia/Dubai',
  'Asia/Kabul',
  'Europe/Tirane',
  'Asia/Yerevan',
  'Antarctica/Casey',
  'Antarctica/Davis',
  'Antarctica/DumontDUrville', 
  'Antarctica/Mawson',
	...
]

Recommended Format

ISO 8601

YYYY-MM-DD
YYMMDD
© VincentVanKoh