webpack.config.js

var path = require('path');

module.exports = {
  // The main "entry point" of your web app. WebPack will pack every module that
  // this file depends on (and its dependencies depend on).
  entry: './app/app.js',
  // Package up the application as 'app.js' in the 'build/js' directory.
  // __dirname is a magic variable that contains the directory that webpack.config.js
  // is located in.
  output: {
    path: path.resolve(__dirname, "build", "js"),
    publicPath: "/js/",
    filename: "app.js"
  },
  // Source Maps map locations in build/js/app.js back to individual application
  // modules. Chrome Developer Tools uses this so you can see your original code
  // in the development tools.
  // We use the "inline-source-map" setting (as opposed to external source maps)
  // so this works in a foolproof way.
  devtool: 'inline-source-map',
  module: {
    // Transforms your application's code using Babel.
    // Babel lets you use new JavaScript features in browsers that do not
    // have them. In particular, Babel lets you use JavaScript modules, which
    // are a recent addition to JavaScript that are not supported by all browsers.
    // In the future, this transformation step will not be necessary.
    // (The babel-loader will also compile your React templates to JavaScript.)
    loaders: [
      {
        // Only transform *.js files.
        test: /\.js$/,
        // Don't transform any of the modules you depend on -- just transform
        // *your* code.
        exclude: /(node_modules|bower_components)/,
        loader: 'babel-loader',
        query: {
          // es2015 == ECMAScript 2015. Lets you use new JavaScript features.
          // The React module runs the React compiler, which translates the
          // HTML in your React modules into code.
          presets: ['es2015', 'react']
        }
      }
    ]
  }
};