transformAliasToOrigin = langs => {
  const result = []
  for (const lang of langs) {
    if (languages[lang]) {
      result.push(lang)
    } else {
      const language = Object.keys(languages).find(name => {
        const l = languages[name]
        if (l.alias) {
          return l.alias === lang || Array.isArray(l.alias) && l.alias.includes(lang)
        }
        return false
      })

      if (language) {
        result.push(language)
      } else {
        // The lang is not exist, the will handle in `initLoadLanguage`
        result.push(lang)
      }
    }
  }

  return result
}
The set of all languages which have been loaded using the below function.

@type {Set<string>}