title: Cannot read properties of null (reading 'message') at SafeSubscriber._next (notifications-query.component.ts:56:21)
body: <p>I get the above error while I am getting some Data from api. This error if the data is null, if the api returns some data then this error is not coming.</p>
  <p>I am using the below piece of code and subscribing the service.</p>
  <pre><code>this.systemMessageService.getSystemMessage().
          subscribe(res =&gt; {
              if (res.message !== null &amp;&amp; res.message !== undefined) {
                  this.systemMessage = res.message;
              } else {
                  this.systemMessage = undefined;
              }
          });
  </code></pre>
  <p>Please help me how I can handle this error</p>