webpack.config.js

const path = require('path');
const CopyWebpackPlugin = require('copy-webpack-plugin');

module.exports = {
     entry: './app/javascripts/app.js',
     output: {
          path: path.resolve(__dirname, 'docs'),
          filename: 'app.js'
     },
     plugins: [
          // Copy our app's index.html to the build folder.
          new CopyWebpackPlugin([{
               from: './app/index.html',
               to: "index.html"
          }])
     ],
     module: {
          rules: [{
                    test: /\.css$/,
                    use: ['style-loader', 'css-loader']
               },
               {
                    test: /\.scss$/,
                    use: ['style-loader', 'css-loader', 'postcss-loader', 'sass-loader']
               },
               {
                    test: /\.woff2?(\?v=[0-9]\.[0-9]\.[0-9])?$/,
                    use: 'url-loader?limit=10000',
               },
               {
                    test: /\.(ttf|eot|svg)(\?[\s\S]+)?$/,
                    use: 'file-loader',
               },

          ],
          loaders: [{
                    test: /\.json$/,
                    use: 'json-loader'
               },
               {
                    test: /\.js$/,
                    exclude: /(node_modules|bower_components)/,
                    loader: 'babel-loader',
                    query: {
                         presets: ['es2015'],
                         plugins: ['transform-runtime']
                    }
               }
          ]
     }
}