webpack.conf.js

const WebpackFilePreprocessorPlugin = require('@jkroepke/webpack-file-preprocessor-plugin');

module.exports = config => {
  config.plugins.push(
    new WebpackFilePreprocessorPlugin({
      pattern: /\.(json)$/,
      process: source => JSON.stringify(JSON.parse(source)),
    })
  );

  return config;
};