webpack.hot.config.js

var {resolve} = require('path');
var webpack = require('webpack');
var reactLoader = require('react-hot-loader');
var ExtractTextPlugin = require('extract-text-webpack-plugin');


module.exports = {
    devtool: 'eval',
    context: __dirname + "/app/js",

    entry: [
        'react-hot-loader/patch',
        'webpack-dev-server/client?http://localhost:9000',
        'webpack/hot/only-dev-server',
        './app.jsx'
    ],

    output: {
        filename: "assets/javascripts/app_bundle.js",
        path: __dirname + '/app',
        pathinfo: true,
        publicPath: 'http://localhost:9000/'
    },
    resolve: {
        extensions: ['.webpack.js', '.web.js', '.js', '.jsx']
    },
    devServer: {
        hot: true,
        publicPath: '/assets/',
        host: 'localhost',
        port: 9000,
        contentBase: resolve(__dirname, 'app/assets/'),
        headers: {
            'Access-Control-Allow-Origin': 'http://localhost:3000',
            'Access-Control-Allow-Credentials': 'true'
        }
    },

    module: {
        // Load the react-hot-loader
        loaders: [
            {
                test: /\.(js|jsx)$/,
                exclude: /node_modules/,
                loaders: ['babel-loader?presets[]=es2015&presets[]=react']
            },
            // Extract css files
            {
                test: /\.css$/,
                loader: ExtractTextPlugin.extract({fallback: 'style-loader', use: 'css-loader'})
            },
            // Optionally extract less files
            // or any other compile-to-css language
            {
                test: /\.less$/,
                loader: ExtractTextPlugin.extract({fallback: 'style-loader', use: 'css-loader'})
            },
            {
                test: /\.(jpg|png|svg)$/,
                loader: 'url-loader'
            }
        ]
    },

    // Require the webpack and react-hot-loader plugins
    plugins: [
        new ExtractTextPlugin("assets/stylesheets/app_bundle.css"),
        new webpack.HotModuleReplacementPlugin(),
        new webpack.NoEmitOnErrorsPlugin(),
        new webpack.NamedModulesPlugin()
    ]
};