title: Angular2 - 'then' does not exist on type 'void'
body: <p>I try simple app where I delete user after clicking on delete button.</p>
  
  <p>When I try to run server like this I get error on <code>then</code> in <code>deleteUser()</code>
  component:</p>
  
  <pre><code> deleteUser(user: User, event: any) {
      event.stopPropagation();
      this.userService
        .deleteUser(user)
        .then(res =&gt; {
          this.httpUsers = this.httpUsers.filter(h =&gt; h !== user);
          if (this.selectedUser === user) { this.selectedUser = null; }
        })
        .catch(error =&gt; this.error = error);
    }
  </code></pre>
  
  <p>service:</p>
  
  <pre><code>  deleteUser(user: User) {
      console.log('Deleting user');
    }
  </code></pre>
  
  <p>Error message:</p>
  
  <blockquote>
    <p>app/users.component.ts(46,8): error TS2339: Property 'then' does not
    exist on type 'void'.</p>
  </blockquote>
  
  <p>Line 46 from error is one above with <code>.then(res =&gt; {</code></p>
  
  <p>While googling I found <a href="https://stackoverflow.com/questions/37986102/property-then-does-not-exist-on-type-void">this question</a> so I removed void from deleteUser function, however nothing changed.</p>
  
  <p><strong>Any hint what I'm doing wrong?</strong></p>