title: Prevent user from typing certain characters into a text input field
body: <p>I'm not sure what this is called. It's really simple. I tried using a pipe, but I got an error. I'm looking for something as simple as:</p>
  
  <pre><code>&lt;input [(ngModel)]="order.name | lettersOnlyPipe"/&gt;
  </code></pre>
  
  <p>That doesn't work. What can I do that would accomplish this?</p>