@applicaster/zapp-react-native-utils/localizationUtils/localeLanguage.ts

Applicaster Zapp React Native utilities package

/**
 * Tools to convert locale, to ISO639-1 native or English
 * Resources:
 * https://en.wikipedia.org/wiki/ISO_639-1
 * https://tools.ietf.org/html/rfc4646
 * https://tools.ietf.org/html/rfc4647
 * https://github.com/meikidd/iso-639-1
 */

import * as R from "ramda";
import { LANGUAGES } from "./const";

type Languages = {
  [code: string]: {
    code: string;
    name: string;
    nativeName: string;
  };
};

type LanguageCode = string;
type LanguageName = Languages["code"]["name"];
type LanguageNativeName = Languages["code"]["nativeName"];

/**
 * Ensures that the language code exists in the LANGUAGES object
 * Using ramda because of the no-prototype-builtins rule we have
 */
export function validate(code: LanguageCode): boolean {
  return R.has(code, LANGUAGES);
}

/**
 * Takes an RFC 4646 language code and converts it to ISO639-1
 * For example: en-GB to en
 */
export function convertToIso(code: LanguageCode): LanguageCode {
  if (code && typeof code === "string") {
    const isoCode = R.compose(
      R.toLower,
      R.when(R.is(Array), R.head),
      R.split(/([-._])/)
    )(code);

    return validate(isoCode) ? isoCode : null;
  }

  return null;
}

/**
 * Takes the locale code and returns the corresponding language, written in their native language
 * This method, always returns a value, either the name or the code you originally sent
 */
export function getNativeName(code: LanguageCode): LanguageNativeName {
  const validCode = convertToIso(code);

  return validCode ? LANGUAGES[validCode].nativeName : code;
}

/**
 * Takes the locale code and returns the corresponding language, written in English
 * This method, always returns a value, either the name or the code you originally sent
 */
export function getName(code: LanguageCode): LanguageName {
  const validCode = convertToIso(code);

  return validCode ? LANGUAGES[validCode].name : code;
}

/**
 * Takes a string name, either in their native language or in English and returns code
 * This method, returns an empty string if it does not find the language
 * This method, also strips locale specific accents when it runs toLowerCase()
 */
export function getCode(name: LanguageName): LanguageCode | string {
  const codes = Object.keys(LANGUAGES);

  const code = codes.find((languageCode) => {
    const englishLang = LANGUAGES[languageCode].name.toLowerCase();
    const nativeLang = LANGUAGES[languageCode].nativeName.toLowerCase();

    return (
      englishLang === name.toLowerCase() || nativeLang === name.toLowerCase()
    );
  });

  return code || "";
}

export function getAllNativeNames(): LanguageNativeName[] {
  return Object.values(LANGUAGES).map((l) => l.nativeName);
}

export function getAllNames(): LanguageName[] {
  return Object.values(LANGUAGES).map((l) => l.name);
}

export function getAllCodes(): string[] {
  return Object.keys(LANGUAGES);
}