title: Variable is not defined, no-undef; How can I bypass this error?
body: <p>I have a react-create-app project that links a proprietary library in my public index.html that lets me use a variable called "SingularPlayer".</p>
  
  <pre><code>&lt;script src="https://www.something.com/libs/singularplayer.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>for example I'm supposed to be able to:</p>
  
  <pre><code>const previewObj = SingularPlayer(iframeId);
  </code></pre>
  
  <p>But I can't because I keep getting this error:</p>
  
  <blockquote>
    <p>Line 67:  'SingularPlayer' is not defined  no-undef</p>
  </blockquote>
  
  <p>I've tried putting these in my package.json but these didn't work either:</p>
  
  <pre><code>  "rules": {
      "no-undef": 0
    },
    "globals": {
      "SingularPlayer": false
    },
    "env": {
      "SingularPlayer": true
    }
  </code></pre>
  
  <p>EDIT: my project won't let me run (npm start) until I fix the error unfortunately</p>