locales

A string with a BCP 47 language tag or an Intl.Locale instance, or an array of such locale identifiers. For the general form and interpretation of the locales argument, see the parameter description on the Intl main page.

options

An object containing the following properties, in the order they are retrieved:

localeMatcher Optional

The locale matching algorithm to use. Possible values are "lookup" and "best fit"; the default is "best fit". For information about this option, see Locale identification and negotiation.

style Optional

The formatting style to use. Possible values are "narrow", "short", and "long"; the default is "long".

type

The type of display names to return from of(). Possible values are "language", "region", "script", "currency", "calendar", and "dateTimeField".

fallback Optional

What to return from of() if the input is structurally valid but there's no matching display name. Possible values are:

"code" (default)

Return the input code itself.

"none"

Return undefined.

languageDisplay Optional

How language names should be displayed. Only usable along with type: "language". Possible values are:

"dialect" (default)

Display special regional dialects using their own name. E.g. "nl-BE" will be displayed as "Flemish".

"standard"

Display all languages using standard format. E.g. "nl-BE" will be displayed as "Dutch (Belgium)".

TypeError

Thrown if options.type is not provided.

RangeError

Thrown if locales or options contain invalid values.

In basic use without specifying a locale, a formatted string in the default locale and with default options is returned.

console.log(new Intl.DisplayNames([], { type: "language" }).of("US"));
// 'us'

Example using dateTimeField as a type option, will return the localized date time names strings.

const dn = new Intl.DisplayNames("pt", { type: "dateTimeField" });
console.log(dn.of("era")); // 'era'
console.log(dn.of("year")); // 'ano'
console.log(dn.of("month")); // 'mês'
console.log(dn.of("quarter")); // 'trimestre'
console.log(dn.of("weekOfYear")); // 'semana'
console.log(dn.of("weekday")); // 'dia da semana'
console.log(dn.of("dayPeriod")); // 'AM/PM'
console.log(dn.of("day")); // 'dia'
console.log(dn.of("hour")); // 'hora'
console.log(dn.of("minute")); // 'minuto'
console.log(dn.of("second")); // 'segundo'

Example using calendar as a type option, will return the localized calendar names strings.

const dn = new Intl.DisplayNames("en", { type: "calendar" });
console.log(dn.of("roc")); // 'Minguo Calendar'
console.log(dn.of("gregory")); // 'Gregorian Calendar'
console.log(dn.of("chinese")); // 'Chinese Calendar'

Example using language as a type with languageDisplay options.

// Using `dialect` option
const dnDialect = new Intl.DisplayNames("en", {
  type: "language",
  languageDisplay: "dialect",
});
console.log(dnDialect.of("en-GB")); // 'British English'

// Using `standard` option
const dnStd = new Intl.DisplayNames("en", {
  type: "language",
  languageDisplay: "standard",
});
console.log(dnStd.of("en-GB")); // 'English (United Kingdom)'

• Intl.DisplayNames
• Intl.supportedValuesOf()
• Intl