Reduce `charmap.json` of `transliteration` w/ Webpack loader

optimize-transliteration-charmap.js

const ucs2decode = require('transliteration/lib/node/utils').ucs2decode;

// getAlphabet is just function that returns array of required chars for transliteration
const transliterationRanges = getAlphabet('а', 'я')
    // A little bit of magic from `transliteration` sources, that used
    // for searching symbols by charmap.json
    .map((char) => ucs2decode(char) >> 8)
    // Leave only unique values
    .filter((char, i, chars) => (
        chars.includes(char, Math.min(i + 1, chars.length)) === false
    ));

exports.optimizeTransliterationCharmap = function optimizeTransliterationCharmap() {
  return {
    module: {
      rules: [
        {
          test: require.resolve('transliteration/data/charmap.json'),
          use: [
            {
              loader: 'modify-json-loader',
              options: {
                // Convert map ranges to loader format
                include: transliterationRanges.map((range) => `/${range}`),
                // A little bit of magic for loader to work
                stringified: true
              }
            }
          ]
        }
      ]
    }
  };
};