Select at least one checkbox validation - angularjs

Question

I have the array of checkboxes from which I want to select at least one checkbox and want to display the validation error
How can I do that? Here is my code
<div class="form-group" ng-class="{ 'has-error' : submitted && form.field.$invalid }">
<div class="col-md-12"><label for="field" >Select at leat one</label></div>
<div class="col-md-2" data-ng-repeat="i in [1,2,3,4]">
<label><input type="checkbox" name="field[$index]" value="{{i}}" data-ng-model="form.field[$index]" required/>Choice {{i+1}}</label>
</div>
<div ng-show="submitted && form.field.$invalid" class="help-block">
<p ng-show="form.field.$error.required">Please select at least one choice<p>
</div>
</div>
</div>

Answer 1

You can use native javascript functions to iterate over your array. First that come in mind are Array.prototype.some() and Array.prototype.filter().
With some, you can determine if one item in your array validates true and with filter you can find all the elements that pass a custom expression and check if the newly created array has a certain length.
E.g.:
var atleastOne = this.form.field.some(function(element) {
return element;
});
if(atleastOne) {
window.alert("validated with some");
}
var filtered = this.form.field.filter(function(element) {
if(element) { return element; }
});
if(filtered.length > 0) {
window.alert('validated with filter');
}
You can flag the variables that show the errors based on the results of your validation. A working demo can be found here.

Answer 2

You can create your checkbox list object array properly then bind it. Please find the demo
<div ng-controller="ChckbxsCtrl">
<div ng-repeat="chk in items">
<div style="width:500px;height:100px;border:1px solid #000;">
<B>{{chk.group}}</B><br>
<label ng-repeat="vale in chk.values">
<input type="checkbox" ng-model="vale.val" />
{{vale.label}}</label>
</div>
<span ng-show="chk.isValid">Select at least one option from {{chk.group}}</span>
</br> </div>
</br>