Ensure at least one checkbox is selected in angular - angularjs

Question

I need to validate that at least one checkbox, in 3, has been selected. I can't use radio buttons because two of the options are can be selected and exclude the third. I'm not really sure if it's best to put these checkboxes into a model array, rather than binding them to separate models and creating a longer ng-required expression. The docs aren't particularly helpful in describing what 'best practise' is for this sort of thing...
Code:
<div class="form-inline form-group">
<div class="row">
<div class="col-xs-12">
<h4 class="card-title left test-list-header">Balcony</h4>
</div>
</div>
<fieldset class="form-group">
<input type="checkbox" id="balconyBalcony" ng-model="balcony">
<label for="balconyBalcony">Balcony</label>
</fieldset>
<fieldset class="form-group">
<input type="checkbox" id="patioBalcony" ng-model="patio">
<label for="patioBalcony">Patio</label>
</fieldset>
<fieldset class="form-group">
<input type="checkbox" id="noBalcony" ng-model="noBalcony" ng-disabled="balcony || patio">
<label for="noBalcony">No</label>
</fieldset>
<fieldset class="form-group" ng-show="noBalcony && !patio && !balcony">
<div class="md-form">
<input
type="text"
id="{{ Plot::FIELD_BALCONY_NOTES }}"
class="form-control"
name="{{ Plot::FIELD_BALCONY_NOTES }}"
inline-edit
inline-edit-callback="UpdateHandler()"
ng-model="Model.BalconyNotes.Value"
ng-class="{ invalid: createPlot.balconyNotes.$invalid && submitted, valid: createPlot.floor.$valid }"
ng-init="Model.BalconyNotes.Value = '{{ old(Plot::FIELD_BALCONY_NOTES) or $Model->BalconyNotes }}'" ng-required="noBalcony">
<label for="{{ Plot::FIELD_BALCONY_NOTES }}" data-error="#{{ Model.BalconyNotes.ValidationMessage }}" class="w-100">Comments</label>
<span class="help-block" ng-show="createPlot.balconyNotes.$invalid && submitted">As there is no balcony or patio, you must enter a comment</span>
</div>
</fieldset>

Answer 1

You could use ng-required built in directive to validate your form.
Like this:
<form novalidate name="myForm" ng-submit="mySubmitFunc()">
<label>Checkbox 1
<input ng-required="!(cb2 || cb3)" ng-model="cb1" type="checkbox">
</label>
<label>Checkbox 2
<input ng-required="!(cb1 || cb3)" ng-model="cb2" type="checkbox">
</label>
<label>Checkbox 3
<input ng-required="!(cb1 || cb2)" ng-model="cb3" type="checkbox">
</label>
<input type="submit" ng-disabled="myForm.$invalid" value="submit">
</form>
Here is a fiddle demonstrating how to handle such logic.

Answer 2

You could add a validation line:
<div ng-show="myForm.$submitted">
<p style="color: red" ng-show="!myForm.balcony && !myForm.patio && !myForm.noBalcony">You must select at least one of the options above.</p>
</div>
That div shows when the user tries to submit and the p shows when none are selected.
Your button will also need an ng-disabled directive with the same condition.