Vulcan/packages/vulcan-lib/lib/modules/detect_locale.js

/*

Helper to detect current browser locale

*/
export const detectLocale = () => {
  var lang;

  if (typeof navigator === 'undefined') {
    return null;
  }

  if (navigator.languages && navigator.languages.length) {
    // latest versions of Chrome and Firefox set this correctly
    lang = navigator.languages[0];
  } else if (navigator.userLanguage) {
    // IE only
    lang = navigator.userLanguage;
  } else {
    // latest versions of Chrome, Firefox, and Safari set this correctly
    lang = navigator.language;
  }

  return lang;
};