title: 'jQuery is not defined' when use ES6 import
body: <p>My code:</p>
  
  <pre><code>import $ from 'jquery'
  import jQuery from 'jquery'
  import owlCarousel from '../../node_modules/owlcarousel/owl-carousel/owl.carousel'
  
  class App {
      …
      _initSlider() {
          $("#partners-carousel").owlCarousel();
      }
  }
  </code></pre>
  
  <p>I have 'jQuery is not defined' in browser console. What's wrong?
  I can use jQuery as $ in methods of this class, but not with name 'jQuery'.</p>