This is a script to translate values in JSON values which I use to localization support for apps built in my own dev studio (stefan-majiros.com)

translate-JSON-files-with-Google-Cloud.js

// follow the 💖 for important parts


const {createWriteStream} = require('fs');

// you need to install this lib: globally or locally
var TJO = require('translate-json-object')();

// 💖 feel free to use any other JSON file
var json_SOURCE_OF_TRUTH = require('../src/localization/translations/en.json');

// array of iso codes
// e.g. [ 'af',  'am','az',  'be', 'bg',  'bn',  'bs',  'ca', 'co',  'cs',  'da',  'de',  'en']

var supportedLanguages = require('./supportedLanguages');
var fs = require('fs');
var path = require('path');

// 💖 name of the folder with translated files
const outputDirectory = 'translations';

TJO.init({
   // 💖
  googleApiKey: '', 
});

(async function main() {
  try {
    const outputDirectoryPath = path.join(__dirname, outputDirectory);
    const translationFolderExists = fs.existsSync(outputDirectoryPath);
    if (!translationFolderExists) {
      fs.mkdirSync(outputDirectoryPath);
    }
	
// 💖
    for (const lang of supportedLanguages) {
      if (fileExists(lang) === false) {
        let data = await TJO.translate(json_SOURCE_OF_TRUTH, lang);
        writeToFile(data, lang);
        sleep(1000);
      } else {
        console.log('File already exits for lang ', lang);
      }
    }
  } catch (error) {
    console.log('error ', error);
  }
   // 💖
  console.log(
    'Do not forget to run prettier on translations folder to make output pretty',
  );
  console.log('Now you can copy translations folder into app.');
})();

function fileExists(lang) {
  return fs.existsSync(pathRelative(lang));
}

function pathRelative(lang) {
  return path.join(__dirname, outputDirectory, lang + '.json');
}

const writeToFile = (data, lang = 'out.txt') => {
  //TODO mkdir translation folder  - if it does not exist, code fails
  const stream = createWriteStream(pathRelative(lang));
  stream.once('open', function (fd) {
    stream.write(JSON.stringify(data));
    stream.end();
    console.log('lang', lang, ' written');
  });
};

function sleep(ms = 1000) {
  return new Promise(resolve => {
    setTimeout(resolve, ms);
  });
}

The whole article could be found here:

https://stefan-majiros.com/blog/implementing-react-native-localization-like-a-pro/