The Intl.getCanonicalLocales() static method returns an array
containing the canonical locale names. Duplicates will be omitted and elements will be
validated as structurally valid language tags.
Syntax
Intl.getCanonicalLocales(locales)
Parameters
locales- : A list of String values for which to get the canonical locale names.
Return value
An array containing the canonical locale names.
Examples
Using getCanonicalLocales
Intl.getCanonicalLocales("EN-US"); // ["en-US"]
Intl.getCanonicalLocales(["EN-US", "Fr"]); // ["en-US", "fr"]
Intl.getCanonicalLocales("EN_US");
// RangeError:'EN_US' is not a structurally valid language tag