title: Aurelia binding: property-getter called repeatedly
body: <p>I'm currently learning and using Aurelia and something kind of weird (maybe normal) is happening.</p>
  
  <p>When using the following code</p>
  
  <pre><code>export class NavBar {
    get username() {
      console.log('o_o')
      return 'name' + Date.now()
    }
  }
  </code></pre>
  
  <p>And in the template <code>${username}</code>, the username is always updating, several times per seconds (and console.log are logged several times as well of course).</p>
  
  <p>The workaround is to simply use a function and not a getter and call <code>${username()}</code> in the template. But is this behaviour normal? So should I use sometimes getter sometimes not?</p>
  
  <p>Thanks!</p>