title: How to avoid circle observe in MVVM
body: <p>I'm iOS developer and use ReactiveCocoa to implement MVVM in Objective C.  </p>
  
  <p>I have a UITextField with property <code>text</code> (view). View model property <code>nameString</code> (view model) observe <code>text</code> (view) change. Model property <code>name</code> (model) observe <code>nameString</code> (view model)  </p>
  
  <p>In inverse way, <code>nameString</code> (view model) observe <code>name</code> (model). UITextField <code>text</code> (view) observe <code>nameString</code> (view model)</p>
  
  <p>Below image show how new text set when user type to text view. The new text will be update to text view again:</p>
  
  <p><a href="https://i.stack.imgur.com/cI5tm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cI5tm.png" alt="enter image description here"></a></p>
  
  <p>So, when user type a new string. The text field will be set this text again.<br>
  How can I prevent it happen?</p>