webpack.config.js

// Webpack uses this to work with directories
const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require("mini-css-extract-plugin");

// This is main configuration object.
// Here you write different options and tell Webpack what to do
module.exports = {

    // Path to your entry point. From this file Webpack will begin his work
    entry: './src/app.js',

    // Path and filename of your result bundle.
    // Webpack will bundle all JavaScript into this file
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'bundle.js'
    },
    watch: true,
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /(node_modules)/,
                use: {
                    loader: 'babel-loader',
                    options: {
                        presets: ['@babel/preset-env']
                    }
                }
            },
            {
                // Apply rule for .sass, .scss or .css files
                test: /\.(sa|sc|c)ss$/,

                // Set loaders to transform files.
                // Loaders are applying from right to left(!)
                // The first loader will be applied after others
                use: [
                    {
                        loader: MiniCssExtractPlugin.loader
                    },
                    {
                        // This loader resolves url() and @imports inside CSS
                        loader: "css-loader",
                    },
                    {
                        // Then we apply postCSS fixes like autoprefixer and minifying
                        loader: "postcss-loader"
                    },
                    {
                        // First we transform SASS to standard CSS
                        loader: "sass-loader",
                        options: {
                            implementation: require("sass")
                        }
                    }
                ]
            },
            {
                test: /\.(png|jpe?g|gif|svg)$/,
                use: [
                    {
                        // Using file-loader for these files
                        loader: "file-loader",

                        // In options we can set different things like format
                        // and directory to save
                        options: {
                            outputPath: 'images'
                        }
                    }
                ]
            },
            {
                test: /\.(woff|woff2|ttf|otf|eot)$/,
                use: [
                    {
                        // Using file-loader too
                        loader: "file-loader",
                        options: {
                            outputPath: 'fonts'
                        }
                    }
                ]
            }
        ]
    },

    plugins: [
        new MiniCssExtractPlugin({
            path: path.resolve(__dirname, 'dist'),
            filename: "bundle.css"
        })
    ],

    // Default mode for Webpack is production.
    // Depending on mode Webpack will apply different things
    // on final bundle. For now we don't need production's JavaScript 
    // minifying and other thing so let's set mode to development
    mode: 'development'
};