title: TypeError require(...).app is not a function while deploying Angular Universal App to Firebase
body: <p><strong>While deploying Angular Universal Angular 13 App to Firebase getting below error</strong></p>
  <pre><code>i  functions: preparing codebase default for deployment
  Error when trying to deploy:
  Error occurred while parsing your function triggers.
  TypeError: require(...).app is not a function
  </code></pre>
  <p><strong>The below line in dist/myapp/fuctions/index.js is causing the problem</strong></p>
  <pre><code>const expressApp = require('./dist/myapp/server/main').app();
  </code></pre>
  <p>There is main.js file exists in /dist/myapp/server folder, not sure what's causing the problem</p>
  <p>I found many related questions in StackOverflow and other sources but not helped fix the issue. Please help!</p>