title: How to add days to Timestamp in Milliseconds Epoch Flutter e create a function
body: <p>I need to create a function that when the thirtieth day is reached from the moment of registration the system will be block the user.
  During user registration a create TimeStamp in millisecond Epoch with</p>
  <pre><code>DateTime.now().millisecondsSinceEpoch.toString(),
  </code></pre>
  <p>this will create into my database the day and the hour where the user creates his account...
  Now I need to add to this TimeStamp 30 days and I need to create a function when</p>
  <p>the TImestamp with these 30 days added</p>
  <p>is == or &gt;= than then registration timestamp it create an exception.</p>
  <p>I have created with this function with FieldValue.serverTimeStamp() but of course I cant detect when this 2 fields are == but not if is greather or lesser because FieldValue doest allow &gt;&lt;.
  Any suggestion?</p>