title: Extend express res.json function
body: <p>I was wondering how to extend the <code>res.json</code> function. I want it to do some string replacements before doing its normal duty.</p>
  
  <p>My idea is to use that for translations</p>
  
  <pre><code>{
  value:'some key'
  }
  </code></pre>
  
  <p>and it comes out </p>
  
  <pre><code>{ 
  value:'translated text'
  }
  </code></pre>
  
  <p>any idea how to do that. </p>