webpack.config.js

const path = require('path')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const extractSass = new ExtractTextPlugin('stylesheets/style.css')

module.exports = {
  entry: {
    all: path.join(__dirname, 'source/javascripts/all.js'),
    style: path.join(__dirname, 'source/stylesheets/style.scss')
  },

  resolve: {
    modules: [
      path.join(__dirname, 'source/javascripts'),
      'node_modules'
    ]
  },

  output: {
    path: path.join(__dirname, '.tmp/dist'),
    filename: 'javascripts/[name].js'
  },

  module: {
    rules: [
      {
        test: /source\/javascripts\/.*\.js$/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['es2015']
          }
        }
      },
      {
        test: /\.png$/,
        use: [
          {
            loader: 'url-loader',
            options: {
              mimetype: 'image/png'
            }
          }
        ]
      },
      {
        test: /\.scss$/,
        use: extractSass.extract(
          {
            use: [
              {
                loader: 'css-loader',
                options: {
                  sourceMap: true
                }
              }, {
                loader: 'sass-loader',
                options: {
                  includePaths: [
                    path.join(__dirname, 'node_modules')
                  ],
                  sourceMap: true
                }
              }
            ],
            fallback: 'style-loader'
          }
        )
      }
    ]
  },

  plugins: [
    extractSass
  ]
}