title: Angular 5 ng-select how to add two values to 'bindLabel'?
body: <p>I want to have ng-select with two values in property bindLabel. I have something like this:</p>
  
  <pre><code>&lt;ng-select placeholder="{{'TASKS.FOR_WHO' | translate }}"
                             name="users"  [items]="users" bindLabel="firstName" &gt;
  
   &lt;/ng-select&gt;
  </code></pre>
  
  <p>But in <strong>bind label</strong> i want to have <strong>bindLabel=</strong> firstName + lastName.
  Like this:</p>
  
  <pre><code>&lt;ng-select placeholder="{{'TASKS.FOR_WHO' | translate }}"
                             name="users"  [items]="users" bindLabel="firstName+lastName"&gt;
  
   &lt;/ng-select&gt;
  </code></pre>
  
  <p>How to achieve this?</p>