title: Help with replacing a text with regex
body: <p>I have the following text in a file called build.xml:</p>
  
  <pre><code>component.rollup=true
  component.rollup.modules.buildfiles=io-base.xml, io-form.xml, io-xdr.xml
  component.rollup_dir=/base
  </code></pre>
  
  <p>I want it to add one file in it so it will become:</p>
  
  <pre><code>component.rollup=true
  component.rollup.modules.buildfiles=io-base.xml, io-form.xml, io-xdr.xml, io-extended.xml
  component.rollup_dir=/base
  </code></pre>
  
  <p>How can I do that with regex?</p>
  
  <p>I'm using javascript.</p>
  
  <p>Thanks!</p>
  
  <p>EDIT:</p>
  
  <p>Forgot to tell you that the files are not static, they may change. Only</p>
  
  <pre><code>component.rollup.modules.buildfiles=
  </code></pre>
  
  <p>will always be there.</p>