自定义指令不是验证形式。 为什么不？

Question

What code changes need to be made to get the custom countparens directive below to provide the extra custom string validation shown below during form validation? The code below DOES successfully alert the user when the input field is empty, but it IS NOT alerting the user when the number of open parens ( and close parens ) is not equal.

I am using AngularJS. I used the documentation at this link (scroll to bottom) to design the code below.

Here is the html for the form:

<table>
    <tr>
        <td width=200>
            <form name="userForm" ng-submit="rectangularForm(userForm.$valid)" novalidate>
                <input type="text" name="fieldname" ng-model="nameofjsontype.fieldname" required />
                <p ng-show="userForm.fieldname.$invalid && !userForm.fieldname.$pristine" class="help-block">Function is a required field.</p>
                <span ng-show="userForm.nameofjsontype.fieldname.$error.countparens">The #( != #) !</span>
                <br>
                <button type="submit" ng-disabled="userForm.$invalid" >Click to submit</button>
            </form>
        </td>
    </tr>
</table>

The javascript file containing the directive includes:

// create angular app
var myApp = angular.module('myApp', []);

// create angular controller
myApp.controller('myController', ['$scope', '$http', function($scope, $http) {
$scope.nameofjsontype = {type:"nameofjsontype", fieldname: 'some (value) here.'};

    $scope.rectangularForm = function(isValid) {
        // check to make sure the form is completely valid
        if (isValid) {
          var funcJSON = {type:"nameofjsontype", fieldname: $scope.nameofjsontype.fieldname};
          $http.post('/server/side/controller', funcJSON).then(function(response) {
            $scope.nameofjsontype = response.data;
          });
        }
    };
}]);

myApp.directive('countparens', function() {
 return {
   require: 'ngModel',
   link: function(scope, elm, attrs, ctrl) {
     ctrl.$validators.countparens = function(modelValue, viewValue) {
       if (ctrl.$isEmpty(modelValue)) {
         // consider empty models to be valid
         return true;
       }

       if (
        ($scope.nameofjsontype.fieldname.match(/\)/g).length) == ($scope.nameofjsontype.fieldname.match(/\(/g).length)
        ) {
         // it is valid
         return true;
       }

       // it is invalid
       return false;
     };
   }
 };
});

Answer 1

Your markup should be using userForm.fieldname.$error.countparens to show the error. The field bound to the userForm is NOT the same as your ngModel value. See plunker for what I mean

<span ng-show="userForm.fieldname.$error.countparens" class="help-block">The #( != #) !</span>

You are also not using your directive on your input element:

<input type="text" name="fieldname" ng-model="nameofjsontype.fieldname" required data-countparens=""/>

In your directive

• you should be using modelValue and not the scope value when doing your matching AND
• you need to cater for when there are no matches to ( or )

.

myApp.directive('countparens', function() {
    return {
      require: 'ngModel',
      link: function(scope, elm, attrs, ctrl) {
          ctrl.$validators.countparens = function(modelValue, viewValue) {
            return ctrl.$isEmpty(modelValue) ||
              ((modelValue.match(/\)/g) || []).length == (modelValue.match(/\(/g) || []).length);
          };
        }
    };
});