Angular 1.5表单验证-如何验证多个输入都是空的或满的

<form name="myForm">
  <input type="text" name="field1" ng-model="data.field1" ng-required="true">
  <input type="text" name="field2" ng-model="data.field2" ng-required="true">
  <input type="text" name="field3" ng-model="data.field3" ng-required="true">
  
  <button type="submit" ng-disabled="myForm.$invalid || !isFieldsStatusValid()">Submit</button>
</form>

$scope.isFieldsStatusValid = function() {
  var fields = [$scope.data.field1, $scope.data.field2, $scope.data.field3];
  var isAllEmpty = fields.every(function(field) {
    return !field;
  });
  var isAllFilled = fields.every(function(field) {
    return !!field;
  });
  
  return isAllEmpty || isAllFilled;
};