title: Regular expression for matching empty json values
body: <p>I have the next problem on PHP:</p>
  
  <p>I need to get a JSON string with '[]' instead of empty values so I need a regular expresion for matching the empty values and changing them for '[]' with preg_replace.</p>
  
  <p>An example of the json could be like this:</p>
  
  <pre><code>[{"id":"8176","token":"","name":null},...]
  </code></pre>
  
  <p>Im trying for so long with regular expressions but i cant find the correct one</p>
  
  <p>the result should be like</p>
  
  <pre><code>[{"id":"8176","token":"[]","name":"[]"},...]
  </code></pre>