webpack.dev.js

const path = require('path');

const HtmlWebpackPlugin = require('html-webpack-plugin');
const ExtractTextPlugin = require('extract-text-webpack-plugin');

module.exports = {
    devtool: 'eval-cheap-module-source-map',
    entry: './src/index.js',
    devServer: {
        port: 8080,
        contentBase: path.join(__dirname, "dist")
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /node_modules/,
                loader: 'babel-loader',
                options: {
                    presets: ['env']
                }
            },
            {
                test: /\.(scss|css)$/,
                use: ExtractTextPlugin.extract({
                    use: [
                        {
                            // translates CSS into CommonJS
                            loader: 'css-loader',
                            options: {
                                sourceMap: true
                            }
                        },
                        {
                            // Runs compiled CSS through postcss for vendor prefixing
                            loader: 'postcss-loader',
                            options: {
                                sourceMap: true
                            }
                        },
                        {
                            // compiles Sass to CSS
                            loader: 'sass-loader',
                            options: {
                                outputStyle: 'expanded',
                                sourceMap: true,
                                sourceMapContents: true
                            }
                        }
                    ],
                    fallback: 'style-loader'
                }),
            },
            {
                // Load all images as base64 encoding if they are smaller than 8192 bytes
                test: /\.(png|jpg|gif)$/,
                use: [
                    {
                        loader: 'url-loader',
                        options: {
                            // On development we want to see where the file is coming from, hence we preserve the [path]
                            name: '[path][name].[ext]?hash=[hash:20]',
                            limit: 8192
                        }
                    }
                ]
            }
        ],
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: './index.html',
            inject: true
        }),
        new ExtractTextPlugin('styles.[contentHash].css', {
            allChunks: true
        }),
    ]
};