How to force user to provide values to Angular Inputs - forms

Question

Using Angular to design a form with 3 inputs (based on Scotch.IO tutorial for Node+Express+Angular).
I would like the user to compulsorily select values for each input before submitting the form. If he doesn't, then I would like to display an error message.
<form>
<div class="form-group">
Start Date: <input type="date" class="form-control input-lg text-center" ng-model="formData.fromDate" placeholder="yyyy-MM-dd">
</div>
<div class="form-group">
End Date: <input type="date" class="form-control input-lg text-center" ng-model="formData.toDate" placeholder="yyyy-MM-dd">
</div>
<div class="form-group">
Report Type: <select class="form-control input-lg text-center" ng-model="formData.reportType">
<option value="csv">CSV</option>
<option value="pdf">PDF</option>
</select>
</div>
<button type="submit" class="btn btn-primary btn-lg" ng-click="findStat()">Add</button>
</form>
In other words, i would not like to pass 'undefined' values back to my Node.js code.
I have tried using 'required' options, which doesn't prevent undefined values from being passed back.

Answer 1

Give your form a name:
<form name="myForm">
Also give your inputs a name, and add validity constraints on them (required, etc.):
<input type="date" name="date" ...
Then in your findStat() function, you can access the form and check if it's valid:
$scope.findStat = function() {
if ($scope.myForm.$invalid) {
$scope.displayError = true;
}
else {
$scope.displayError = false;
...
}
}
See http://code.angularjs.org/1.2.15/docs/api/ng/directive/form and http://code.angularjs.org/1.2.15/docs/api/ng/type/form.FormController for more information.