title: how to customise angular2 textmask
body: <p>I am new in angular2. I want phone number text mask. according to this</p>
  
  <pre><code>pattern= (?:(?=^91)[0-9]{12}|(?!^91)[0-9]{10,15})$
  </code></pre>
  
  <p>How do I customize it in this pattern format?</p>