[javascript] Day Name from Date in JS

I need to display the name of the day given a date (like "05/23/2014") which I get from a 3rd party.

I've tried using Date, but I only get the date.

What is the correct way to get the name of the day?

To get the day from any given date, just pass the date into a new Date object:

let date = new Date("01/05/2020");
let day = date.toLocaleString('en-us', {weekday: 'long'});
console.log(day);
// expected result = tuesday

To read more, go to mdn-date.prototype.toLocaleString()(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleString)

let weekday = new Date(dateString).toLocaleString('en-us', {weekday:'long'});
console.log('Weekday',weekday);

One more option is to use the inbuilt function Intl.DateTimeFormat, e.g.:

function getDayName(dateString) {
    const [date, options] = [new Date(dateString), {weekday: 'long'}];
    return new Intl.DateTimeFormat('en-Us', options).format(date);
}

<label for="inp">Enter a date string in the format "MM/DD/YYYY" or "YYYY-MM-DD" and press "OK":</label><br>
<input type="text" id="inp" value="01/31/2021">
<button onclick="alert(getDayName(document.getElementById('inp').value))">OK</button>

One line solution :

const day = ["sunday","monday","tuesday","wednesday","thursday","friday","saturday"][new Date().getDay()]

var days = [
    "Sunday",
    "Monday",
    "...", //etc
    "Saturday"
];

console.log(days[new Date().getDay()]);

Simple, read the Date object in JavaScript manual

To do other things with date, like get a readable string from it, I use:

var d = new Date();
d.toLocaleString();

If you just want time or date use:

d.toLocaleTimeString();
d.toLocaleDateString();

You can parse dates either by doing:

var d = new Date(dateToParse);

or

var d = Date.parse(dateToParse);

Ahum, three years later...

Why nobody uses the methods provided by the standard javascript Date class (except Callum Linington)?

See https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleDateString

Getting the day name from a date:

function getDayName(dateStr, locale)
{
    var date = new Date(dateStr);
    return date.toLocaleDateString(locale, { weekday: 'long' });        
}

var dateStr = '05/23/2014';
var day = getDayName(dateStr, "nl-NL"); // Gives back 'Vrijdag' which is Dutch for Friday.

Getting all weekdays in an array:

function getWeekDays(locale)
{
    var baseDate = new Date(Date.UTC(2017, 0, 2)); // just a Monday
    var weekDays = [];
    for(i = 0; i < 7; i++)
    {       
        weekDays.push(baseDate.toLocaleDateString(locale, { weekday: 'long' }));
        baseDate.setDate(baseDate.getDate() + 1);       
    }
    return weekDays;
}

var weekDays = getWeekDays('nl-NL'); // Gives back { 'maandag', 'dinsdag', 'woensdag', 'donderdag', 'vrijdag', 'zaterdag', 'zondag'} which are the days of the week in Dutch.

For American dates use 'en-US' as locale.

Not the best method, use an array instead. This is just an alternative method.

http://www.w3schools.com/jsref/jsref_getday.asp

var date = new Date();
var day = date.getDay();

You should really use google before you post here.

Since other people posted the array method I'll show you an alternative way using a switch statement.

switch(day) {
    case 0:
        day = "Sunday";
        break;
    case 1:
        day = "Monday";
        break;

    ... rest of cases

    default:
        // do something
        break;
}

The above works, however, the array is the better alternative. You may also use if() statements however a switch statement would be much cleaner then several if's.

use the Date.toLocaleString() method :

new Date(dateString).toLocaleString('en-us', {weekday:'long'})

Just use it:

function getWeekDayNames(format = 'short', locale = 'ru') {_x000D_
  const names = [];_x000D_
  const date = new Date('2020-05-24');_x000D_
  let days = 7;_x000D_
_x000D_
  while (days !== 0) {_x000D_
    date.setDate(date.getDate() + 1);_x000D_
    names.push(date.toLocaleDateString(locale, { weekday: format }));_x000D_
    days--;_x000D_
  }_x000D_
_x000D_
  return names;_x000D_
}

About formats you can read here Documentation DateTimeFormat

you can use an object

var days = {
   'Mon': 'Monday',
   'etc..': 'etc..',
   'Fri': 'Friday'
}

var date = new Date().toString().split(' ')[0]; //get day abreviation first
console.log(days[date]);

let weekday = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'][new Date().getDay()]

Shortest one liner

Change the UTC day from 6 to 5 if you want Array to start from Sunday.

const getWeekDays = (locale) => [...Array(7).keys()].map((v)=>new Date(Date.UTC(1970, 0, 6+v)).toLocaleDateString(locale, { weekday: 'long' }));

console.log(getWeekDays('de-DE')); 

Take a look at this :

var event = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));

var options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };

console.log(event.toLocaleDateString('de-DE', options));
// expected output: Donnerstag, 20. Dezember 2012

console.log(event.toLocaleDateString('ar-EG', options));
// expected output: ??????? ?? ??????? ????

console.log(event.toLocaleDateString('ko-KR', options));
// expected output: 2012? 12? 20? ???

Source : Mozilla Doc

Solution No.1

var today = new Date();

  var day = today.getDay();

  var days = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"];

  var dayname = days[day];

  document.write(dayname);

Solution No.2

      var today = new Date();

  var day = today.getDay();

  switch(day){
    case 0:
    day = "Sunday";
    break;

    case 1:
    day = "Monday";
    break;

    case 2:
    day ="Tuesday";
    break;

    case 3:
    day = "Wednesday";
    break;

    case 4:
    day = "Thrusday";
    break;

    case 5:
    day = "Friday";
    break;

    case 6:
    day = "Saturday";
    break;
  }


document.write(day);

I'm not a fan of over-complicated solutions if anyone else comes up with something better, please let us know :)

any-name.js

var today = new Date().toLocaleDateString(undefined, {
    day: '2-digit',
    month: '2-digit',
    year: 'numeric',
    weekday: 'long'
});

any-name.html
<script>
    document.write(today);
</script>

Try using this code:

var event = new Date();
var options = { weekday: 'long' };
console.log(event.toLocaleDateString('en-US', options));

this will give you the day name in string format.

Easiest and simplest way:

var days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
var dayName = days[new Date().getDay()];