title: Uncaught TypeError: Popper is not a constructor
body: <p>I try to edit CSS stlye of Tippy.js.
  So I npm install tippy and import it to my html like this  </p>
  
  <pre><code>&lt;script src="/min/tippy.js/umd/index.all.js"&gt;&lt;/script&gt; 
  </code></pre>
  
  <p>But, it has some error.</p>
  
  <pre><code>Uncaught TypeError: Popper is not a constructor
      at createPopperInstance (createTippy.ts:677)
      at mount (createTippy.ts:694)
      at Object.show (createTippy.ts:961)
      at new_control.js:128
      at Array.forEach (&lt;anonymous&gt;)
      at createGraph (new_control.js:101)
      at Object.success (new_control.js:6)
      at u (jquery.min.js:2)
      at Object.fireWith [as resolveWith] (jquery.min.js:2)
      at k (jquery.min.js:2)
  </code></pre>
  
  <p>So, I have tried to npm install popper in my directory working file but,it's not work at all. Did I miss something? </p>