version 2

generateAdditionalSubtitleFiles.js

const fs = require('fs')
const translationsGroups = [
    ['fr_FR','fr_CA'],
    ['es_ES','es_MX','es_CL','es_CO','eu_ES','es_UY','es_VE','gl_ES'],
    ['pt_BR','pt_PT'],
    ['zh_CN','zh_TW','zh_HK']
]

const copyTranslation = (inputCountryCode, outputCountryCode, file) => fs.copyFileSync(file, file.replace(inputCountryCode, outputCountryCode, fs.constants.COPYFILE_EXCL))
const copyTranslationForGroup = (file, translationsGroup, inputCountryCode) => translationsGroup.forEach(translation => copyTranslation(inputCountryCode, translation, file))

fs.readdir(__dirname, (err, files) => {
    if (err) throw err
    files.forEach(file => {
        translationsGroups.forEach((translationGroup) => {
            translationGroup.forEach((translation) => {
                if (file.includes(translation)) copyTranslationForGroup(file, translationGroup, translation)
            })
        })
    })
})