next-i18next

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The easiest way to translate your NextJs apps.
38 lines (32 loc) • 1.03 kB
JavaScript
export const lngsToLoad = (initialLng, fallbackLng, otherLanguages) => {
  const languages = [];

  if (initialLng) {
    languages.push(initialLng);
  }

  if (fallbackLng) {
    if (typeof fallbackLng === 'string' && fallbackLng !== initialLng) {
      languages.push(fallbackLng);
    }

    if (Array.isArray(fallbackLng)) {
      languages.push(...fallbackLng);
    } else if (initialLng) {
      if (typeof fallbackLng[initialLng] === 'string') {
        languages.push(fallbackLng[initialLng]);
      } else if (Array.isArray(fallbackLng[initialLng])) {
        languages.push(...fallbackLng[initialLng]);
      }
    }

    if (fallbackLng.default) {
      languages.push(fallbackLng.default);
    }
  }

  if (initialLng && initialLng.includes('-') && Array.isArray(otherLanguages)) {
    const [languageFromLocale] = initialLng.split('-');
    otherLanguages.forEach(otherLanguage => {
      if (otherLanguage === languageFromLocale) {
        languages.push(otherLanguage);
      }
    });
  }

  return languages;
};