title: Angular: Replacing environment.ts with configuration specific files with ng serve
body: <p>I have an Angular app which uses <code>environment.ts</code> file to set stuff like urls of servers.</p>
  
  <p>I know that I can use <strong>build configurations</strong> specified in <code>angular.json</code> to replace files at build time, e.g. replace <code>environment.ts</code> with <code>environment.prod.ts</code>.</p>
  
  <p>I would like something similar with <code>ng serve</code>, e.g. launching</p>
  
  <pre><code>ng serve --configuration=production
  </code></pre>
  
  <p>and having <code>environment.prod.ts</code> replacing <code>environment.ts</code>.</p>
  
  <p>I this possible? Are there better ways to drive with command lines parameters which settings are used in <code>ng serve</code>?</p>