webpack.config.js

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

const mode = process.env.mode || 'production';

module.exports = {
    entry: ['babel-polyfill', './src/index.js'],
    mode,
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'bundle.[hash].js'
    },
    module: {
        rules: [
            {
                test: /\.jsx?$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader',
                    options: {
                        presets: ['env', 'react', 'stage-0']
                    }
                }
            },
            {
                test: /\.scss$/,
                use: [
                    'style-loader',
                    {loader: 'css-loader', options: {importLoaders: 1}},
                    'sass-loader',
                    'postcss-loader'
                ]
            },
            {
                test: /\.(png|jpg|gif|svg|woff|woff2|eot|ttf)$/,
                use: [
                    {
                        loader: 'file-loader',
                        options: {}
                    }
                ]
            }
        ]
    },
    resolve: {
        extensions: ['.js', '.jsx']
    },
    plugins: [
        new CleanWebpackPlugin(['dist']),
        new HtmlWebpackPlugin({
            template: './src/index.html'
        })
    ],
    devServer: {
        contentBase: path.join(__dirname, 'dist'),
        historyApiFallback: true,
        port: 9000,
        disableHostCheck: true,
        progress: true,
        watchContentBase: true
    }
};