title: What is the name of the ${} notation in Angular2 (TypeScript)
body: <p>I have seen the following syntax used in an <a href="https://www.youtube.com/watch?v=4M-VzJq4XIk" rel="nofollow noreferrer">Angular2 tutorial</a></p>
  
  <p><code>(click)="choose('${RED}')"</code></p>
  
  <p>which references </p>
  
  <p><code>export const RED = '#1976d2';</code></p>
  
  <p>I have not seen this syntax in the documentation and I'm not sure how to look it up. Is it deprecated?</p>