webpack.common.js

const path = require('path');
const { CleanWebpackPlugin } = require('clean-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');

const ExtractTextPlugin = require("extract-text-webpack-plugin");
module.exports = {
    entry: {
        app: './src/index.js'
    },
    plugins: [
        new ExtractTextPlugin("styles.css"),
        new CleanWebpackPlugin(),
        new HtmlWebpackPlugin({
            title: 'Production'
        })
    ],
    module: {
        rules: [
            {
                test: /\.css$/,
                use: ExtractTextPlugin.extract({
                    fallback: "style-loader",
                    use: "css-loader"
                })
            }
            // {
            //     test: /\.css$/,
            //     use: ['style-loader', 'css-loader']
            // }
            , 
            { test: /\.js$/, use: 'babel-loader' }
        ]
    },
    output: {
        filename: '[name].bundle.js',
        path: path.resolve(__dirname, 'dist')
    }
};