old_contents: import webpack from 'webpack';
  import WebpackDevServer from 'webpack-dev-server';
  import opn from 'opn';
  import webpackConfig from '../webpack.config.babel';
  
  const host = 'localhost';
  const port = 8080;
  const url = `http://${host}:${port}/`;
  
  const config = webpackConfig({dev: true});
  
  config.entry.unshift(
    `webpack-dev-server/client?${url}`,
    'webpack/hot/only-dev-server',
  );
  
  const devServer = new WebpackDevServer(webpack(config), {
    hot: true,
    historyApiFallback: true,
    stats: {
      color: true,
    },
  });
  
  devServer.listen(port, host, (err) => {
    if (err) {
      console.error(err); // eslint-disable-line no-console
  
      return;
    }
  
    console.log(`Listening at ${url}`); // eslint-disable-line no-console
    opn(url);
  });
  
new_contents: import webpack from 'webpack';
  import WebpackDevServer from 'webpack-dev-server';
  import opn from 'opn';
  import webpackConfig from '../webpack.config.babel';
  
  const host = 'localhost';
  const port = 3000;
  const url = `http://${host}:${port}/`;
  
  const config = webpackConfig({dev: true});
  
  config.entry.unshift(
    `webpack-dev-server/client?${url}`,
    'webpack/hot/only-dev-server',
  );
  
  const devServer = new WebpackDevServer(webpack(config), {
    hot: true,
    historyApiFallback: true,
    stats: {
      color: true,
    },
  });
  
  devServer.listen(port, host, (err) => {
    if (err) {
      console.error(err); // eslint-disable-line no-console
  
      return;
    }
  
    console.log(`Listening at ${url}`); // eslint-disable-line no-console
    opn(url);
  });
  
subject: Update port number