title: Ember.js - Model inside component
body: <p>I am making an app just for practice and i have a doubt in a component's function "didReceiveAttr". When i pass my MODEL in my template and then i erase some element in it the function doesnt work, but if i pass "model.length" in the template and then erase something the function work!</p>
  
  <p>My component template</p>
  
  <pre><code>&lt;h1&gt;Tasks ({{totalTask}})&lt;/h1&gt;
  </code></pre>
  
  <p>My component JS </p>
  
  <pre><code>  totalTask: null,
  
    didReceiveAttrs(){
      this._super(...arguments);
      this.set('totalTask', this.get('model.length'));
      console.log(this.get('model'));
    }
  </code></pre>
  
  <p>My primary template</p>
  
  <pre><code>{{task-list model=model}}
  </code></pre>
  
  <p>or </p>
  
  <pre><code>{{task-list model=model.length}}
  </code></pre>