Configuring Webpack 2.3.x in dev mode

webpack.config.dev.js

import webpack from 'webpack';
import path from 'path';
import nodeExternals from 'webpack-node-externals';

export default {    
    devtool: "cheap-module-eval-source-map",
    entry: [
        //code order here is critical
        "eventsource-polyfill", //for hot reloading in IE
        "webpack-hot-middleware/client?reload=true", //reloads page if HMR fails
        "./src/index.jsx"
    ],
    target: "web",
    output: {
        path: path.resolve(__dirname, "/dist"),
        publicPath: "/",
        filename: "bundle.js"
    },
    devServer: {
        contentBase: "./src"
    },
    plugins: [
        new webpack.HotModuleReplacementPlugin(),
        new webpack.NoEmitOnErrorsPlugin(),
        new webpack.LoaderOptionsPlugin({
            debug: true
        })
    ],
    module: {
        rules: [
            {
                test: /\.(js|jsx)?$/,
                include: path.join(__dirname, "src"),
                use: "babel-loader"
            },
            {
                test: /\.css$/,                          
                use: [
                    {
                        loader: 'style-loader'
                    },
                    {
                        loader: 'css-loader'
                    }
                ]
            },
            {
                test: /\.eot(\?v=\d+\.\d+)?$/,
                use: "file-loader"
            },            
            {
                test: /\.otf(\?[a-z0-9]+)?$/,
                use: "file-loader?name=fonts/[name].[ext]"
            },
            {
                test: /\.(woff|woff2)$/,
                use: "url-loader?prefix=font/&limit=5000"
            },
            {
                test: /\.ttf(\?v=\d+\.\d+\.\d+)?$/,
                use: "url-loader?limit=10000&mimetype=application/octet-stream"
            },
            {
                test: /\.svg(\?v=\d+\.\d+\.\d+)?$/,
                use: "url-loader?limit=10000&mimetype=image/svg+xml"
            }            
        ]
    }
};

For react apps, also add .babelrc with the following:

{
    "presets": ["es2015", "react"] ,
    "env": {
           "development": {
                    "presets": ["react-hmre"]
            }
     }
}