Toggle class on input depending on input's value - angularjs

Question

I am still new to Angular but I have an existing application that uses Angular 1.5 pretty heavily.
I have a basic form that I need to add a class to depending on the following criteria:
The form can only have an End Date value or an Active for value. It cannot have both. I was thinking I need to disable the input box of the input not being used.
Ex. If a user inputs a date into the End Date input, then the Active for input will become disabled.
I looked into ng-if but every example I came across was for checking if the entered input variable was empty or equal to a value in a .js controller, not checking if the current entered variable was equal to another entered variable in the form.
<div class="form-group">
<label>End date:</label>
<div class="input-group">
<input type="text" class="form-control" is-open="endDateOpened" uib-datepicker-popup="MM/dd/yyyy" ng-model="updatePatientLabel.active_end_date"/>
<span class="input-group-btn">
<button type="button" class="btn btn-search" ng-click="openEndDate($event)"><i class="fa fa-calendar"></i></button>
</span>
</div>
</div>
<div class="form-group">
<label>Or will be active for:</label>
<input name="expirationTimeNumber" type="number" class="form-control time" ng-model="updatePatientLabel.expiration_time_number"/>
</div>
Here is a screenshot of my modal where this happens. Ignore the other inputs as they are not affected by the conditions I've laid out.
Thanks
Form Screen Shot

Answer 1

You can use ng-disabled.
//initialize your dates with null
$scope.updatePatientLabel = {};
$scope.updatePatientLabel.active_end_date = null;
$scope.updatePatientLabel.expiration_time_number = null;
HTML:
<input id="endDate" ng-disabled="updatePatientLabel.expiration_time_number !== null" ng-model="updatePatientLabel.active_end_date" />
<input id="activeDate" ng-disabled="updatePatientLabel.active_end_date !== null" ng-model="updatePatientLabel.expiration_time_number" />

Answer 2

You have a few options. Classes, as you mentioned, or ng-if. The ng-if seems more elegant, like so:
<div class="form-group" ng-if="updatePatientLabel.active_end_date != ''">
<label>End date:</label>
<div class="input-group">
<input type="text" class="form-control" is-open="endDateOpened" uib-datepicker-popup="MM/dd/yyyy" ng-model="updatePatientLabel.active_end_date"/>
<span class="input-group-btn">
<button type="button" class="btn btn-search" ng-click="openEndDate($event)"><i class="fa fa-calendar"></i></button>
</span>
</div>
</div>
<div class="form-group" ng-if="updatePatientLabel.expiration_time_number > 0">
<label>Or will be active for:</label>
<input name="expirationTimeNumber" type="number" class="form-control time" ng-model="updatePatientLabel.expiration_time_number"/>
</div>
Otherwise, you could do an inline conditional outputting "hidden" inside the class attribute only if the value is not present. Something like this:
<div class="form-group {{updatePatientLabel.active_end_date != '' ? '' : 'hidden'}}">
<label>End date:</label>
<div class="input-group">
<input type="text" class="form-control" is-open="endDateOpened" uib-datepicker-popup="MM/dd/yyyy" ng-model="updatePatientLabel.active_end_date"/>
<span class="input-group-btn">
<button type="button" class="btn btn-search" ng-click="openEndDate($event)"><i class="fa fa-calendar"></i></button>
</span>
</div>
</div>
<div class="form-group {{updatePatientLabel.expiration_time_number > 0 ? '' : 'hidden'}}">
<label>Or will be active for:</label>
<input name="expirationTimeNumber" type="number" class="form-control time" ng-model="updatePatientLabel.expiration_time_number"/>
</div>
I use both in my projects, and either way is perfectly acceptable. Though, ng-if does seem more elegant and a bit more suited for this scenario.