webpack.config.js

const path = require('path');
var configImport = {
  development: require('./webpack.config.dev'),
  production: require('./webpack.config.prod')
}

module.exports = {
  ...configImport[process.env.NODE_ENV],
  module: {
    rules: [
      {
        test: /\.m?js$/,
        exclude: /(node_modules|bower_components)/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env'],
            cacheDirectory: true,
            plugins: ['react-hot-loader/babel']
          }
        }
      },
      {
        test: /\.css$/,
        use: [
          require.resolve('style-loader'),
          {
            loader: require.resolve('css-loader'),
            options: {
              importLoaders: 1,
            },
          },
          {
            loader: 'postcss-loader',
            options: {
              plugins: () => [require('autoprefixer')]
            }
          }
        ]
      },
      {
        test: /\.(png|jpg|gif)$/,
        loader: 'file-loader',
        options: {
          name: '[path][name].[ext]'
        }
      }
    ]
  },
  resolve: {
    alias: {
      components: path.resolve(__dirname, './src/components'),
      assets: path.resolve(__dirname, './src/assets'),
    }
  }
};