title: It said parcelRequire is not defined when i'm using socket.io
body: <p><a href="https://i.stack.imgur.com/BCr7D.png" rel="nofollow noreferrer">the error</a></p>
  <p>I use import like this</p>
  <pre class="lang-js prettyprint-override"><code>import { io } from &quot;./lib/socket.io.esm.min.js&quot;;
  </code></pre>
  <p>And I copied socket.io/client/socket.io.esm.min.js to ./lib/socket.io.esm.min.js</p>