webpack.config.js

var path = require('path');

/**
 * @see http://webpack.github.io/docs/configuration.html
 * for webpack configuration options
 */
module.exports = {
  // 'entry' specifies the entry point, where webpack starts reading all
  // dependencies listed and bundling them into the output file.
  // The entrypoint can be anywhere and named anything - here we are calling it
  // '_application' and storing it in the 'javascripts' directory to follow
  // Rails conventions.
  entry: './app/client/javascripts/entry.jsx',

  // 'output' specifies the filepath for saving the bundled output generated by
  // wepback.
  // It is an object with options, and you can interpolate the name of the entry
  // file using '[name]' in the filename.
  // You will want to add the bundled filename to your '.gitignore'.
  output: {
    filename: '[name].bundle.js',
    // We want to save the bundle in the same directory as the other JS.
    path: __dirname + '/app/assets/javascripts',
  },
  module: {
    rules: [
      {
        test: /\.jsx?$/,
        use: [
          {
            loader: "babel-loader"
          }
        ],
      }
    ]
  }
};