title: vendorSourceMap deprecated in Angular CLI 7.2
body: <p>Starting with <code>Angular 7.2</code>, the <code>vendorSourceMap</code> option is deprecated:</p>
  
  <pre><code>&gt; ng serve --vendor-source-map
  
  Option "vendorSourceMap" is deprecated.
  </code></pre>
  
  <p>Official documentation of <a href="https://angular.io/cli/serve" rel="noreferrer">ng serve</a> says <code>vendorSourceMap</code> is deprecated, but gives no alternative way of resolving library sources:</p>
  
  <blockquote>
    <p>--vendorSourceMap=true|false  </p>
    
    <p><strong>Deprecated</strong></p>
    
    <p>Resolve vendor packages sourcemaps.</p>
    
    <p>Default: false</p>
  </blockquote>
  
  <p>What is the correct, non-deprecated way, then to resolve vendor source maps in Angular 7.2?</p>