Date.prototype.toLocaleString()
The toLocaleString()
method returns a string with a
language sensitive representation of this date.
The new locales
and options
arguments
let applications specify the language whose formatting conventions should be used and
customize the behavior of the function.
In older implementations, which ignore the locales
and
options
arguments, the locale used and the form of the string
returned are entirely implementation-dependent.
Syntax
toLocaleString()
toLocaleString(locales)
toLocaleString(locales, options)
Parameters
The locales
and options
arguments
customize the behavior of the function and let applications specify the language whose
formatting conventions should be used. In implementations which ignore the
locales
and options
arguments, the
locale used and the form of the string returned are entirely implementation-dependent.
See the Intl.DateTimeFormat()
constructor for details on these parameters and how to use them.
The default value for each date-time component property is undefined
.
But if the weekday
, year
, month
, and
day
properties are all undefined
, then year
,
month
, and day
are assumed to be "numeric"
.
Return value
A string representing the given date according to language-specific conventions.
Examples
Using toLocaleString()
In basic use without specifying a locale, a formatted string in the default locale and with default options is returned.
let date = new Date(Date.UTC(2012, 11, 12, 3, 0, 0));
// toLocaleString() without arguments depends on the
// implementation, the default locale, and the default time zone
console.log(date.toLocaleString());
// → "12/11/2012, 7:00:00 PM" if run in en-US locale with time zone America/Los_Angeles
Checking for support for locales and options arguments
The locales
and options
arguments are
not supported in all browsers yet. To check whether an implementation supports them
already, you can use the requirement that illegal language tags are rejected with a
RangeError
exception:
function toLocaleStringSupportsLocales() {
try {
new Date().toLocaleString('i');
} catch (e) {
return e.name === 'RangeError';
}
return false;
}
Using locales
This example shows some of the variations in localized date and time formats. In order
to get the format of the language used in the user interface of your application, make
sure to specify that language (and possibly some fallback languages) using the
locales
argument:
let date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));
// Formats below assume the local time zone of the locale;
// America/Los_Angeles for the US
// US English uses month-day-year order and 12-hour time with AM/PM
console.log(date.toLocaleString('en-US'));
// → "12/19/2012, 7:00:00 PM"
// British English uses day-month-year order and 24-hour time without AM/PM
console.log(date.toLocaleString('en-GB'));
// → "20/12/2012 03:00:00"
// Korean uses year-month-day order and 12-hour time with AM/PM
console.log(date.toLocaleString('ko-KR'));
// → "2012. 12. 20. 오후 12:00:00"
// Arabic in most Arabic-speaking countries uses Eastern Arabic numerals
console.log(date.toLocaleString('ar-EG'));
// → "٢٠/١٢/٢٠١٢ ٥:٠٠:٠٠ ص"
// For Japanese, applications may want to use the Japanese calendar,
// where 2012 was the year 24 of the Heisei era
console.log(date.toLocaleString('ja-JP-u-ca-japanese'));
// → "24/12/20 12:00:00"
// When requesting a language that may not be supported, such as
// Balinese, include a fallback language (in this case, Indonesian)
console.log(date.toLocaleString(['ban', 'id']));
// → "20/12/2012 11.00.00"
Using options
The results provided by toLocaleString()
can be customized using the
options
argument:
let date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));
// Request a weekday along with a long date
let options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };
console.log(date.toLocaleString('de-DE', options));
// → "Donnerstag, 20. Dezember 2012"
// An application may want to use UTC and make that visible
options.timeZone = 'UTC';
options.timeZoneName = 'short';
console.log(date.toLocaleString('en-US', options));
// → "Thursday, December 20, 2012, GMT"
// Sometimes even the US needs 24-hour time
console.log(date.toLocaleString('en-US', { hour12: false }));
// → "12/19/2012, 19:00:00"
Avoid comparing formatted date values to static values
Most of the time, the formatting returned by toLocaleString()
is
consistent. However, this might change in the future, and isn't guaranteed for all
languages; output variations are by design, and allowed by the specification.
Most notably, the IE and Edge browsers insert bidirectional control characters around dates, so the output text will flow properly when concatenated with other text.
For this reason, you cannot expect to be able to compare the results of
toLocaleString()
to a static value:
"1/1/2019, 01:00:00" === new Date("2019-01-01T01:00:00Z").toLocaleString("en-US");
// true in Firefox and others
// false in IE and Edge
Note: See also this StackOverflow thread for more details and examples.
Specifications
Specification |
---|
ECMAScript Language Specification # sec-date.prototype.tolocalestring |
ECMAScript Internationalization API Specification # sup-date.prototype.tolocalestring |
Browser compatibility
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