Tips for avoiding errors when a data field is missing in Angular 2

Presently, I am in the process of developing an application using Angular 2 and integrating it with a database. However, a particular line of code is causing an error:

<span class="col-sm-6">{{workorder.timeWindowAppointment.date}}</span>

The specific error message reads:

"Cannot read property 'date' of null"

I understand that this error is valid because the date property does not exist at the moment. Nevertheless, I plan to include a date property in the future.

My goal is for Angular 2 not to generate an error, but simply display nothing on the page instead.

angulartypescripterror-handling

Answer №1

Utilize the secure navigation tool (?) to safeguard your template against null or undefined values:

<span class="col-sm-6">{{workorder?.timeWindowAppointment?.date}}</span>

Explore more information on this topic here.

Answer №2

To define the variable in your scope, you can use the following code snippet:

$scope.workorder.timeWindowAppointment.date;

This allows you to have placement data in advance, possibly set as = new Date().toIsoString();

Alternatively, in your HTML code:

<span class="col-sm-6">{{(workorder.timeWindowAppointment.date) || otherValue}}</span>

This performs a similar function without explicitly defining the variable, offering an alternative value if needed.

Another way is to include this code in your HTML:

<span class="col-sm-6" ng-if="workorder.timeWindowAppointment.date">{{workorder.timeWindowAppointment.date}}</span>

This displays the data only if there is a defined value while preserving the layout of the HTML content.

One more option could be:

<span class="col-sm-6" ng-show="workorder.timeWindowAppointment.date">{{workorder.timeWindowAppointment.date}}</span>

Here, the data is shown but the HTML element remains hidden if the value is not defined.

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