title: AngularJS conditional attribute
body: <p>Is it possible to get conditional attribute (not class)? </p>
  
  <p>e.g.:</p>
  
  <pre><code>&lt;form-field {true: 'required'}[field.required]&gt;&lt;/form-field&gt;
  </code></pre>
  
  <p>expected results</p>
  
  <pre><code>&lt;form-field required&gt;&lt;/form-field&gt;
  </code></pre>
  
  <p>or</p>
  
  <pre><code>&lt;f orm-field &gt;&lt;/form-field&gt;
  </code></pre>
  
  <p>now I've got an </p>
  
  <blockquote>
    <p>Error: The string contains invalid characters.</p>
  </blockquote>
  
  <p>This is in html file not in template which I can compile.</p>