How to format a JavaScript date

If you need slightly less control over formatting than the currently accepted answer, Date#toLocaleDateString can be used to create standard locale-specific renderings. The locale and options arguments let applications specify the language whose formatting conventions should be used, and allow some customization of the rendering.

Options key examples:

1. day:
   The representation of the day.
   Possible values are "numeric", "2-digit".
2. weekday:
   The representation of the weekday.
   Possible values are "narrow", "short", "long".
3. year:
   The representation of the year.
   Possible values are "numeric", "2-digit".
4. month:
   The representation of the month.
   Possible values are "numeric", "2-digit", "narrow", "short", "long".
5. hour:
   The representation of the hour.
   Possible values are "numeric", "2-digit".
6. minute: The representation of the minute.
   Possible values are "numeric", "2-digit".
7. second:
   The representation of the second.
   Possible values are "numeric", 2-digit".

All these keys are optional. You can change the number of options values based on your requirements, and this will also reflect the presence of each date time term.

Note: If you would only like to configure the content options, but still use the current locale, passing null for the first parameter will cause an error. Use undefined instead.

For different languages:

1. "en-US": For American English
2. "en-GB": For British English
3. "hi-IN": For Hindi
4. "ja-JP": For Japanese

You can use more language options.

For example

var options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };
var today  = new Date();

console.log(today.toLocaleDateString("en-US")); // 9/17/2016
console.log(today.toLocaleDateString("en-US", options)); // Saturday, September 17, 2016
console.log(today.toLocaleDateString("hi-IN", options)); // शनिवार, 17 सितंबर 2016

You can also use the toLocaleString() method for the same purpose. The only difference is this function provides the time when you don't pass any options.

// Example
9/17/2016, 1:21:34 PM

References:

• toLocaleString()

• toLocaleDateString()

For custom-delimited date formats, you have to pull out the date (or time) components from a DateTimeFormat object (which is part of the ECMAScript Internationalization API), and then manually create a string with the delimiters you want.

To do this, you can use DateTimeFormat#formatToParts. You could destructure the array, but that is not ideal, as the array output depends on the locale:

{ // example 1
   let f = new Intl.DateTimeFormat('en');
   let a = f.formatToParts();
   console.log(a);
}
{ // example 2
   let f = new Intl.DateTimeFormat('hi');
   let a = f.formatToParts();
   console.log(a);
}

Better would be to map a format array to resultant strings:

function join(t, a, s) {
   function format(m) {
      let f = new Intl.DateTimeFormat('en', m);
      return f.format(t);
   }
   return a.map(format).join(s);
}

let a = [{day: 'numeric'}, {month: 'short'}, {year: 'numeric'}];
let s = join(new Date, a, '-');
console.log(s);

You can also pull out the parts of a DateTimeFormat one-by-one using DateTimeFormat#format, but note that when using this method, as of March 2020, there is a bug in the ECMAScript implementation when it comes to leading zeros on minutes and seconds (this bug is circumvented by the approach above).

let d = new Date(2010, 7, 5);
let ye = new Intl.DateTimeFormat('en', { year: 'numeric' }).format(d);
let mo = new Intl.DateTimeFormat('en', { month: 'short' }).format(d);
let da = new Intl.DateTimeFormat('en', { day: '2-digit' }).format(d);
console.log(`${da}-${mo}-${ye}`);

When working with dates and times, it is usually worth using a library (eg. luxon, date-fns, moment.js is not recommended for new projects) because of the many hidden complexities of the field.

Note that the ECMAScript Internationalization API, used in the solutions above is not supported in IE10 (0.03% global browser market share in Feb 2020).