JavaScript Date and Time

In this tutorial, you will learn about the date and time in JavaScript with the assistance of examples.

In this article, you will learn-

1 Introduction
2 Creating Date Objects
3 new Date()
4 new Date(milliseconds)
5 new Date(date string)
- 5.1 ISO Date Formats
6 Short and Long date format
7 new Date(year, month, day, hours, minutes, seconds, milliseconds)
8 JavaScript Date Methods
9 Example: Date Methods
10 Formatting a Date
11 AutoCorrection in Date Object

Introduction

Date and time are an ordinary piece of our regular daily existences and in this way highlight noticeably in computer programming. In JavaScript, you may need to make a site with a schedule, a training plan, or an interface to set up arrangements. These applications need to show significant times based on the user’s current timezone, or perform calculations around appearances and flights or start and end times. Furthermore, you may have to utilize JavaScript to produce a report at a specific time each day, or channel through as of now open restaurants and establishment

In JavaScript, date and time are represented by the Date object. The Date object provides the date and time data and furthermore gives different techniques.

A JavaScript date characterizes the EcmaScript epoch that represents milliseconds since 1 January 1970 UTC. This date and time are equivalent to the UNIX epoch (predominant base value for computer-recorded date and time values).

Creating Date Objects

There are four ways to create a date object.

new Date()
new Date(milliseconds)
new Date(Date string)
new Date(year, month, day, hours, minutes, seconds, milliseconds)

new Date()

You can make a date object using the new Date() constructor. For instance,

const timeNow = new Date();
console.log(timeNow); // shows current date and ti

Output

Wed Jun 27 2021 2:04:58

Here, new Date() creates a new date object with the current date and local time.

new Date(milliseconds)

The Date object contains a number that represents milliseconds since 1 January 1970 UTC.

new Date(milliseconds) creates a new date object by adding the milliseconds to the zero time. For example,

const time1 = new Date(0);

// epoch time
console.log(time1); // Thu Jan 01 1970 05:30:00

// 100000000000 milliseconds after the epoch time
const time2 = new Date(100000000000)
console.log(time2); // Sat Mar 03 1973 15:16:40

Note: 1000 milliseconds is equal to 1 second.

new Date(date string)

new Date(date string) creates a new date object from a date string.

In JavaScript, there are generally three date input formats.

ISO Date Formats

You can make a date object by passing ISO date designs. For instance,

// ISO Date(International Standard)
const date = new Date("2020-07-01");

// the result date will be according to UTC
console.log(date); // Wed Jul 01 2020 05:45:00

You can likewise pass just the year and month or just the year. For instance,

const date = new Date("2020-07");
console.log(date); // Wed Jul 01 2020 05:45:00 

const date1 = new Date("2020");
console.log(date1); // Wed Jul 01 2020 05:45:00

You can likewise pass specific time to ISO dates.

const date = new Date("2020-07-01T12:00:00Z");
console.log(date); // Wed Jul 01 2020 17:45:00

Note: Date and time are separated with the capital letter T. And UTC time is defined with capital Z.

Short and Long date format

The other two date formats are short date format and long date format.

// short date format "MM/DD/YYYY"
const date = new Date("03/25/2015");
console.log(date); // Wed Mar 25 2015 00:00:00 

// long date format "MMM DD YYYY"
const date1 = new Date("Jul 1 2020");
console.log(date1); // Wed Jul 01 2020 00:00:00 

// month and day can be in any order
const date2 = new Date("1 Jul 2020");
console.log(date2); // Wed Jul 01 2020 00:00:00 

// month can be full or abbreviated. Also month names are insensitive.
// comma are ignored
const date3 = new Date("July 1 2020");
console.log(date3); // Wed Jul 01 2020 00:00:00 

const date4 = new Date("JULY, 1, 2020");
console.log(date4); // Wed Jul 01 2020 00:00:00

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

new Date(year, month,…) creates a new date object by passing specific date and time. For example,

const time1 = new Date(2020, 1, 20, 4, 12, 11, 0);
console.log(time1); // Thu Feb 20 2020 04:12:11

The passed contention has a particular request.

In the event that four numbers are passed, it represents the year, month, day, and hours. For instance,

const time1 = new Date(2020, 1, 20, 4);
console.log(time1); // Thu Feb 20 2020 04:00:00

Likewise, if two contentions are passed, it represents to year and month. For instance,

const time1 = new Date(2020, 1);
console.log(time1); // Sat Feb 01 2020 00:00:00

Note: If you pass just a single argument, it is treated as milliseconds. Consequently, you need to pass two arguments to use this date format.
In JavaScript, months are counted from 0 to 11. January is 0 and December is 11.

JavaScript Date Methods

There are various methods available in JavaScript Date object.

Method	Description
now()	Returns the numeric value corresponding to the current time (the number of milliseconds elapsed since January 1, 1970 00:00:00 UTC)
getFullYear()	Gets the year according to local time
getMonth()	Gets the month, from 0 to 11 according to local time
getDate()	Gets the day of the month (1–31) according to local time
getDay()	Gets the day of the week (0-6) according to local time
getHours()	Gets the hour from 0 to 23 according to local time
getMinutes	Gets the minute from 0 to 59 according to local time
getUTCDate()	Gets the day of the month (1–31) according to universal time
setFullYear()	Sets the full year according to local time
setMonth()	Sets the month according to local time
setDate()	Sets the day of the month according to local time
setUTCDate()	Sets the day of the month according to universal time

Example: Date Methods

const timeInMilliseconds = Date.now();
console.log(timeInMilliseconds); // 1593765214488

const time = new Date;

// get day of the month
const date = time.getDate();
console.log(date); // 30

// get day of the week
const year = time.getFullYear();
console.log(year); // 2020

const utcDate = time.getUTCDate();
console.log(utcDate); // 30

const event = new Date('Feb 19, 2020 23:15:30');
// set the date
event.setDate(15);
console.log(event.getDate()); // 15

// Only 28 days in February!
event.setDate(35);

console.log(event.getDate()); // 7

Formatting a Date

In contrast to other programming languages, JavaScript doesn’t give a built-in function for formatting a date.

In any case, you can extract singular pieces and use it like this.

const currentDate = new Date();
const date = currentDate.getDate();
const month = currentDate.getMonth();
const year = currentDate.getFullYear();

// show in specific format
let monthDateYear = (month+1) + '/' + date + '/' + year;

console.log(monthDateYear); // 7/3/2020

Note: The above program gives the conflicting lengths as date and month have single-digit and twofold digit.

AutoCorrection in Date Object

At the point when you allocate out of range values in the Date object, it auto-corrects itself. For instance,

const date = new Date(2008, 0, 33);
// Jan does not have 33 days

console.log(date);

Output

Sat Feb 02 2008

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