title: Angular 5 binding model using conditionnal
body: <p>I'm using Angular 5 and i'm trying to bind a specific model according to a value that i have in the localstorage.</p>
  
  <p>I tried this, i have no error but it's doesnt seem to bind to the right model :</p>
  
  <pre><code>    &lt;mat-select [(ngModel)]="userStorage == null ? book.autorid : book.id"&gt;
         &lt;mat-option *ngFor="let book of bookList" [value]="book.value"&gt;
                          {{book.viewValue}}
         &lt;/mat-option&gt;
       &lt;/mat-select&gt;
  </code></pre>