webpack.config.js

const path = require("path");
const ExtractTextPlugin = require('extract-text-webpack-plugin');

module.exports = (env, args) => {
    const isProduction = (env === 'production');
    const CSSExtract = new ExtractTextPlugin('styles.css');

    return {
        entry: "./src/app.js",
        output: {
            path: path.join(__dirname, "public", 'dist'),
            filename: "bundle.js"
        },
        module: {
            rules: [{
                loader: "babel-loader",
                test: /\.js$/,
                exclude: /node_modules/
            }, {
                test: /\.s?css$/,
                use: CSSExtract.extract({
                    use: [
                        {
                            loader: 'css-loader',
                            options: {
                                sourceMap: true,
                            }
                        },
                        {
                            loader: 'sass-loader',
                            options: {
                                sourceMap: true,
                            }
                        },
                    ]
                })
            }]
        },
        plugins: [
            CSSExtract,
        ],
        devtool: isProduction ? 'source-map' : "inline-source-map",
        devServer: {
            contentBase: path.join(__dirname, "public"),
            historyApiFallback: true,
            publicPath: '/dist/'
        }
    }
}