title: Conditional flex in Angular material
body: <p>Given the bootstrap layout definition</p>
  
  <pre><code>ng-class="{'col-sm-6':vm.data.mode === 'ADD', 'col-sm-3': vm.data.mode === 'EDIT'}"
  </code></pre>
  
  <p>What's the angular material equivalent? (To set flex="50" if vm.data.mode === 'ADD' and set flex="25" if vm.data.mode === 'EDIT')</p>