title: Angular 2 variable in template is undefined
body: <p>I am declaring a variable in my component.</p>
  
  <p>E.g.</p>
  
  <pre><code>let link = 'https://google.com'
  </code></pre>
  
  <p>But if I use it in my template, it is not there</p>
  
  <p>E.g</p>
  
  <pre><code>{{ link }} -&gt; has no output
  href="#{{link}}" -&gt; resolved into href="#"
  [attr.href]="link" -&gt; resolves into nothing
  [attr.href]="link+'#'" -&gt; resolves into href="undefined/#"
  </code></pre>
  
  <p>What am I doing wrong?</p>
  
  <p>Thanks for your help</p>