title: Regex input mask for angular?
body: <p>The <code>ui-mask</code> in `Angular UI Utils' project (<a href="http://angular-ui.github.io/ui-utils/" rel="noreferrer">link</a>) is a bit too limited. </p>
  
  <p>For example, the first digit of a US phone number should be 2-9. In <code>ngPattern</code>, it should be </p>
  
  <pre><code>ng-pattern="/^\([2-9]\d{2}\)\d{3}-\d{4}(x\d{1,4})?$/"
  </code></pre>
  
  <p>So how can I write an input mask to prevent users from entering 0 or 1 in the first digit? Is there some better input mask we should use for Angular?</p>