webpack.common.js

const path = require('path');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');

const port = process.env.PORT || 3000;

module.exports = {
  entry: __dirname + '/src/index.js',
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: 'bundle.js',
  },
  module: {
    rules: [
      {
        test: /\.(js)/,
        exclude: /node_modules/,
        use: ['babel-loader'],
      }, {
        test: /\.css$/,
        use: [{
          loader: 'style-loader',
        }, {
          loader: 'css-loader',
          options: {
            import: true,
          },
        }],
      },
    ],
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: 'src/index.html',
    }),
    new webpack.ProvidePlugin({
      'React': 'react',
    }),
  ],
  devServer: {
    host: 'localhost',
    port: port,
    historyApiFallback: true,
    open: true,
  },
};