webpack.common.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = {
    entry: './public/src/js/index.jsx',
    output: {
        filename: 'App.js',
        path: __dirname + '/public/dist'
    },
    resolve: {
        extensions: ['.js', '.jsx']
    },
    module: {
        rules: [
            {
                test: /\.(js|jsx)$/,
                exclude: /node_modules/,
                use: {
                    loader: "babel-loader"
                }
            },
            {
                test: /\.s[ac]ss$/i,
                use: [
                    MiniCssExtractPlugin.loader,
                    {
                        loader: 'css-loader',
                        options: {
                            sourceMap: true,
                        },
                    },
                    {
                        loader: 'sass-loader',
                        options: {
                            sourceMap: true,
                        },
                    },
                ]
            }
        ]
    },
    plugins: [
        new MiniCssExtractPlugin({
            filename: '[name].css',
            chunkFilename: '[id].css'
        })
    ]
};