TypeScript library for language tags from BCP47
npm install typesbcp47Class LanguageUtils provides static methods for parsing and validating language tags from BCP47.
| Method | Description |
|---|---|
getTagDescription(tag: string): string |
Returns a language description for the tag if the tag is a valid language tag. Returns undefined otherwise. |
normalizeCode(code: string): string |
Returns a normalized code if the code is valid. |
isCJK(code: string): boolean |
Returns true if the language is Chinese, Japanese, Korean, Vietnamese or Aiunu. Returns false otherwise. |
isBiDi(code: string): boolean |
Returns true if the language is written from right to left (Arabic, Hebrew, Persian, Urdu), false otherwise. |
getLanguages(): Array<Language> |
Returns an array of Language objects from the list maintained by ICU (International Components for Unicode). |
getLanguage(code: string): Language |
Returns a Language object by its code if the code is valid. Returns undefined otherwise. |
getCommonLanguages(): Array<Language> |
Returns an array of most common Language objects. |
You can combine these methods to validate language tags:
import { LanguageUtils } from 'typesbcp47';
const tag = 'en-US';
const description = LanguageUtils.getTagDescription(tag);
if (description) {
console.log(`Language tag ${tag} is valid. Description: ${description}`);
} else {
console.log(`Language tag ${tag} is invalid.`);
}
// a common problem with language tags is wrong casing for the code
// this can be fixed by normalizing the code
const normalizedCode = LanguageUtils.normalizeCode(tag);
if (normalizedCode) {
// language exists
if (tag === normalizedCode) {
// language tag is OK
console.log(`Language tag ${tag} is valid.`);
} else {
// language tag is not normalized
console.log(`Language code is incorrect, it should be ${normalizedCode}`)
}
} else {
console.log(`Code ${tag} is invalid.`);
}