webpack.config.js

const path = require('path');
const ExtractTextPlugin = require('extract-text-webpack-plugin');

module.exports = {
  context: path.join(__dirname, 'app', 'frontend'),
  entry: './entry.js',
  output: {
    path: path.join(__dirname, 'app', 'assets', 'javascripts'),
    filename: 'bundle.js',
  },
  plugins: [
    new ExtractTextPlugin('../stylesheets/bundle.scss'),
  ],
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: [{
          loader: 'babel-loader?cacheDirectory=true',
          options: { presets: ['es2015', 'react'] },
        }],
      },
      {
        test: /\.css$/,
        loader: ExtractTextPlugin.extract({
          fallback: 'style-loader',
          use: 'css-loader',
        }),
      },
      {
        test: /\.scss$/,
        loader: ExtractTextPlugin.extract({
          fallback: 'style-loader',
          use: [
            { loader: 'css-loader' },
            { loader: 'sass-loader', options: { includePaths: ['node_modules', 'app/frontend/stylesheets/ext/'] } },
          ],
        }),
      },
      {
        test: /\.(png|woff|woff2|eot|ttf|svg)$/,
        loader: 'url-loader',
      },
    ],
  },
};