i18next-scanner Sync

i18n-sync.js

/**
 *
 * Sync translations between what i18next-scanner gets and what already exists
 * - i18next-scanner scans everything and all all in i18n/{{lang}}/missing/{{ns}}.json
 * - Missing translations values are always null
 * - Existing translations are kept in i18n/{{lang}}/{{ns}}.json
 * - If a string gets removed in missing/{{ns}}.json it will get removed in existing one
 *
 * HOW TO USE THIS SCRIPT
 *
 * 1) Config your i18next-scanner to have a structure like:
 *   i18n
 *    - en
 *      - namespace1.json
 *      - namespace2.json
 *    + fr
 *    + es
 *
 * 2) Set `i18nFolder` variable below
 * 3) Add shortcut to your package.json: `"i18n": "i18next-scanner && node i18n-sync.js"`
 * 4) yarn run i18n  OR   npm run i18n
 * 5) Enjoy
 */
const path = require('path');
const fs = require('fs');
const chalk = require('chalk');

// _____ my i18n folder root: CHANGE ME____________
const i18nFolder = path.join(__dirname, 'resources', 'client', 'i18n');
// ________________________________________________


// Title
console.log(chalk.greenBright.bgBlack.underline('                                  '));
console.log(chalk.greenBright.bgBlack('                                  '));
console.log(chalk.greenBright.bgBlack.bold('         🇫🇷  SYNCING I18N  🇬🇧         '));
console.log(chalk.greenBright.bgBlack.underline('                                  '));

// Read i18n folder
fs.readdir(i18nFolder, function(err, languages) {
  // For each locale
  languages.forEach(lang => {
    // Set path with languages
    const existingTranslationsFolder = `${i18nFolder}/${lang}`;
    const missingTranslationsFolder = `${i18nFolder}/${lang}/missing`;

    // Read files in missing folder
    fs.readdir(missingTranslationsFolder, function(err, files) {
      // For each file, merge new JSON (from scanner) to existing one (my translations)
      files.forEach(file => {
        let missingTranslationsObj, existingTranslationObj;
        try {
          console.log(
            chalk.yellow.bold(
              `-> 📕 Reading missing translations from i18n/${lang}/missing/${file}`
            )
          );
          missingTranslationsObj = JSON.parse(fs.readFileSync(`${missingTranslationsFolder}/${file}`));
          console.log(
            chalk.cyanBright.bold(
              `-> 📗 Reading existing translations from i18n/${lang}/${file}`
            )
          );
          existingTranslationObj = JSON.parse(fs.readFileSync(`${existingTranslationsFolder}/${file}`));
        } catch (err) {
          console.log(chalk.red.bold('💥 Formatting error in i18n JSON files, check linting!'));
          return null;
        }

        const existingKeys = Object.keys(existingTranslationObj).length;
        const missingKeys = Object.keys(missingTranslationsObj).length;

        // Log number of keys
        console.log(
          'Scanned keys: ',
          existingKeys,
          '| Existing keys:',
          missingKeys,
          missingKeys < existingKeys ? '| -> Removing unused keys' : ''
        );
        console.log(' ');

        /**
         *  Remove unused keys
         *
         * if missing has less keys, remove keys from existing
         */
        Object.keys(existingTranslationObj).forEach(key => {
          if (missingTranslationsObj[key] === undefined) {
            delete existingTranslationObj[key];
          }
        });

        // Existing translation overwrites properties of the missing object -> Merging
        const mergedObject = { ...missingTranslationsObj, ...existingTranslationObj };
        // Turn the object back into a string, prettify with 2 spaces
        const mergeObjectString = JSON.stringify(mergedObject, null, 2);
        // Write the new JSON into the existing file
        fs.writeFile(`${existingTranslationsFolder}/${file}`, mergeObjectString, 'utf8', function(err) {
            if (err) {
              console.err('An error occured while writing merge translations into JSON file.');
              return err;
            }
            displayResult(existingKeys, missingKeys, lang, file);
        });
      });
    });
  });
});

function displayResult(existingKeys, missingKeys, lang, file) {
  let operation = '';
  operation += missingKeys < existingKeys ? `Removed ${existingKeys - missingKeys} keys` : '';
  operation += missingKeys > existingKeys ? `Added ${missingKeys - existingKeys} new keys` : '';
  operation += missingKeys === existingKeys ? `No changes made` : '';

  console.log(
    chalk.greenBright.bold(
      `👌 Syncing i18n files: ${operation} in file: i18n/${lang}/${file}`
    )
  );
}