ots/src/webpack.config.js

const path = require('path')
const webpack = require('webpack');

function resolve(dir) {
  return path.join(__dirname, dir)
}

module.exports = {
  entry: './app.js',
  output: {
    filename: 'app.js',
    path: path.resolve(__dirname, '..', 'frontend')
  },
  plugins: [
    new webpack.optimize.OccurrenceOrderPlugin(),
    new webpack.DefinePlugin({
      'process.env': {
        'NODE_ENV': JSON.stringify('production')
      }
    })
  ],
  optimization: {
    minimize: true
  },
  module: {
    rules: [{
        test: /\.(s?)css$/,
        use: [
          'style-loader',
          'css-loader',
          'sass-loader',
        ],
      },
      {
        test: /\.js$/,
        exclude: /(node_modules|bower_components)/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: [
              ['env', {
                "targets": {
                  "browsers": [">0.25%", "not ie 11", "not op_mini all"]
                }
              }]
            ]
          }
        }
      },
    ]
  }
}