title: as keyword in angular 4?
body: <p>Currently am learning about Angular 4 introduced a new keyword : <code>as</code>.</p>
  
  <p><strong>AS keyword</strong> – A new addition to the template syntax is the <code>as keyword</code> is use to simplify to the <code>let</code> syntax.</p>
  
  <p>I have just implement this below code.</p>
  
  <pre><code>&lt;div *ngIf="users | async as usersModel"&gt;
      &lt;h2&gt;{{ usersModel.name }}&lt;/h2&gt; &lt;small&gt;{{ usersModel.age }}&lt;/small&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I can't get much details from anywhere for this below questions.</p>
  
  <h2>Questions:</h2>
  
  <ul>
  <li>What is the difference between of <code>users</code> object and <code>userModel</code> object*. </li>
  <li>What is the main use of <code>as</code> keyword?</li>
  <li>what is the difference between <code>as</code> and <code>let</code> in template?</li>
  </ul>