title: Angular component naming limitations - 'selector [your component name] is invalid'
body: <p>In <code>Angular 6</code> (6.0.7) I'm trying to generate a component via the CLI. I type in <code>ng g c t1-2-3-user</code> and get the error message <strong><em><code>Selector (app-t1-2-3-user) is invalid.</code></em></strong></p>
  
  <p>Is there something inherently not allowed in this name? I've already created a parent module called <code>t1-myModule</code> via <code>ng g module t1-myModule</code> and it was created successfully. Within that module is where I'm trying to generate this component. </p>
  
  <p>I've tried creating a different name like <code>ng g c t1-testComponent</code> and it works fine - so the CLI doesn't appear to be broken. Something about naming a component <code>t1-2-3-user</code> in my setup is not liked by Angular.</p>
  
  <p><strong>EDIT:</strong> <strong>after further testing, it appears Angular doesn't like the first character after a dash <code>-</code> to be a number. Possibly a similar limitation as in JavaScript variables. I assume since it gets compiled into JavaScript? Can anyone elaborate on/confirm this component naming constraint?</strong></p>