package.json

{
  "dependencies": {
    "babel-core": "*",
    "babel-loader": "*",
    "babel-preset-env": "*",
    "babel-preset-react": "*",
    "css-loader": "*",
    "react": "*",
    "react-dom": "*",
    "style-loader": "*",
    "webpack": "*"
  }
}

webpack.config.js

var path = require('path');

var paths = {
  srcDir:  path.resolve(__dirname, 'src'),
  distDir: path.resolve(__dirname, 'dist')
};

module.exports = {
  entry: './src/index',

  output: {
    path: paths.distDir,
    filename: 'bundle.js'
  },

  devtool: 'cheap-module-source-map',

  module: {
    rules: [
      {
        include: paths.srcDir,
        test: /\.js$/,
        use: {
          loader: 'babel-loader',
          options: { presets: ['env', 'react'] }
        }
      },
      {
        include: paths.srcDir,
        test: /\.css$/,
        use: [
          { loader: 'style-loader' },
          { loader: 'css-loader' }
        ]
      }
    ]
  }
};