title: React state update on object
body: <p>If I have the following Person object in state </p>
  
  <pre><code>this.state = {
      Person: {
          FirstName: "John",
          LastName: "Doe"
      }
  }
  </code></pre>
  
  <p>Is it valid do the following...?</p>
  
  <pre><code>this.state.Person.FirstName = "Jane"
  </code></pre>
  
  <p>If not, why?</p>