@lyra/base/lib/locale/languageResolver.js

Lyra plugin containing the base components and roles for a Lyra configuration

'use strict';

// Figure out which locale the user prefers.
// Return a promise in order to support asynchronous resolution.

const nav = typeof navigator === 'undefined' ? {} : navigator;
const defaultLanguage = 'en-US';

function resolveLanguage(supportedLanguages = null) {
  let language = nav.language || nav.browserLanguage || defaultLanguage;
  if (supportedLanguages && !supportedLanguages.includes(language)) {
    language = supportedLanguages[0];
  }
  return Promise.resolve(language);
}

module.exports = {
  resolveLanguage
};