title: what is ... syntax? (found in Angular2)
body: <p>I don't know if this syntax or symbol or whatever belongs to <code>Angular2</code> or something else...</p>
  
  <p>but I wonder with, </p>
  
  <p>what <strong><code>...</code></strong> syntax is and how it works behind the scene? </p>
  
  <pre><code>ngOnChanges(...args:any[])
  {
     console.log(args);
  }
  </code></pre>