title: What's the difference between Single-File Optimization vs Whole Module Optimization
body: <p>I notice there are two settings of optimization in the project settings :</p>
  
  <ul>
  <li>Single-File Optimization</li>
  <li>Whole Module Optimization</li>
  </ul>
  
  <p><a href="https://i.stack.imgur.com/8SQoV.png" rel="noreferrer"><img src="https://i.stack.imgur.com/8SQoV.png" alt="enter image description here"></a></p>
  
  <p>What's the difference? And which one should we choose under what circumstances? </p>