title: Object is possibly Null
body: <p>I want to get the id from the url and then use that to navigate to a different specific view
  I have the following function</p>
  <pre><code>getStudent(): void {
    const id = + this.route.snapshot.paramMap.get('id');
    this.studentService.getStudent(id)
       .subscribe(student =&gt; this.SpecificStudent = student);
  </code></pre>
  <p>I have tried to make sure it is not null by using the assertion</p>
  <p>// !</p>
  <pre><code>const id = + this.route.snapshot.paramMap.get('id')!;
  </code></pre>
  <p>If I do this, it doesn’t show an error, but alert(id) gives 0 which is wrong</p>