title: Knockout subscribe to observable object
body: <p>I have an object:</p>
  
  <pre><code>{ model: settings: { "FirstName": "Joe", "LastName": "Bloggs" } };
  </code></pre>
  
  <p>in my view model I make settings an observable:</p>
  
  <pre><code>this.Settings = ko.observable(ko.mapping.fromJS(model.settings));
  </code></pre>
  
  <p>Which makes <code>FirstName</code> and <code>LastName</code> observables too.</p>
  
  <p>In my view I bind by doing:</p>
  
  <pre><code>&lt;p data-bind="text: Settings().FirstName"&gt;&lt;/p&gt;
  </code></pre>
  
  <p>to read a value from <code>Settings</code> I do:</p>
  
  <pre><code>`this.Settings().FirstName()`
  </code></pre>
  
  <p>The problem comes in when I want to subscribe when <code>FirstName</code> OR <code>LastName</code> changes.</p>
  
  <p>I know I can do <code>this.Settings.FirstName.subscribe...</code> but that's painful once you get more than two things you're observing.</p>
  
  <p>Is there a way to do <code>this.Settings.subscribe...</code>? or should I be using a custom binding?</p>