title: Purpose of pre-loading Node.js modules with command line
body: <p>Looking at the Node.js documentation for command line options to node</p>
  
  <p><a href="https://nodejs.org/api/cli.html" rel="noreferrer">https://nodejs.org/api/cli.html</a></p>
  
  <p>I see </p>
  
  <blockquote>
    <p>-r, --require module#</p>
    
    <p>Preload the specified module at startup.</p>
    
    <p>Follows require()'s module resolution rules. module may be either a
    path to a file, or a node module name.</p>
  </blockquote>
  
  <p>I am pretty certain that with some Node.js frameworks, this option is suggested, but I cannot figure out why it's used. I can't find any use cases online, although I have a slight suspicion that it may be useful for a library I am writing. </p>
  
  <p>Does anyone know what it's used for?</p>