title: popper.js in bootstrap 4 gives SyntaxError Unexpected token export
body: <p>I tried install bootstrap 4, and included following links</p>
  
  <pre><code>&lt;script src="libs/jquery/dist/jquery.min.js"&gt;&lt;/script&gt;
  &lt;script src="libs/tether/dist/js/tether.min.js" &gt;&lt;/script&gt;
  &lt;script src="libs/popper.js/dist/popper.js"&gt;&lt;/script&gt;
  &lt;script src="libs/bootstrap/dist/js/bootstrap.min.js" &gt;&lt;/script&gt;
  </code></pre>
  
  <p>But The following error occurs :</p>
  
  <blockquote>
    <p>Uncaught syntaxError: Unexpected token export</p>
  </blockquote>
  
  <p><a href="https://i.stack.imgur.com/42loV.png" rel="noreferrer"><img src="https://i.stack.imgur.com/42loV.png" alt="enter image description here"></a></p>
  
  <p>Any ideas how to fix it?</p>