title: Vue not loading when using extract() in Laravel Mix
body: <p>I have a nearly vanilla webpack.mix.js and resources/js/app.js setup going in my Laravel project.</p>
  
  <p>webpack.mix.js:</p>
  
  <pre><code>const mix = require('laravel-mix');
  
  mix.js('resources/js/app.js', 'public/js')
     .sass('resources/sass/app.scss', 'public/css');
  </code></pre>
  
  <p>resources/js/app.js:</p>
  
  <pre><code>require('./bootstrap');
  
  window.Vue = require('vue');
  
  Vue.component('profile', require('./components/profile/Profile.vue').default);
  
  const app = new Vue({
      el: '#app'
  });
  </code></pre>
  
  <p>But if I tack on <code>.extract()</code> to the end in my webpack.mix.js, everything compiles successfully but Vue doesn't load at all in the browser.  Remove the <code>.extract()</code> and everything works again.  What am I doing wrong?</p>