Angular Form Validation with Materialize

index.html

<form ng-submit="CONTROLLER.submitTopic(); topicForm.$setPristine();" name="topicForm" novalidate>
  <div class="input-field">
    <input type="text" name="name" ng-class="{'valid': topicForm.name.$valid, 'invalid': topicForm.name.$invalid && topicForm.name.$dirty}" ng-model="CONTROLLER.topicForm.name" ng-minlength=3 ng-maxlength=15 required>

    <label for="name" ng-class="{'green-text text-lighten-2': topicForm.name.$valid, 'red-text text-lighten-2': topicForm.name.$invalid && topicForm.name.$dirty}">Topic Name</label>

    <span ng-show="topicForm.name.$error.minlength && topicForm.name.$dirty">Topic must be at least 3 characters</span>
    <span ng-show="topicForm.name.$error.maxlength && topicForm.name.$dirty">Topic must be less than 15 characters</span>

    <input type="submit" class="btn orange darken-1 right" ng-class="{'disabled': topicForm.$invalid, 'waves-effect waves-light': topicForm.$valid}" value="Add Topic" ng-disabled="topicForm.$invalid">
  </div>
</form>