title: Firestore Rules - Datatype Validation
body: <p>I've read multiple questions in Stack Overflow and the <a href="https://firebase.google.com/docs/reference/rules/" rel="noreferrer">documentation</a> but I couldn't find multiple validations that I can imagine that exist.</p>
  
  <p>Per example, it is possible to check <code>if request.resource.data.description is string</code> but can is it possible to do the same when it comes to <code>number</code>, <code>float</code>, <code>timestamp</code> or even <code>array</code>/<code>list</code>? I couldn't even find the <code>string</code> one in the documentation so I can imagine it is missing more than just that one.</p>