The worth of the scope is evident, yet it remains undefined when trying to access it

Question

The worth of the scope is evident, yet it remains undefined when trying to access it

Currently, I am in the process of developing an AngularJS directive. However, I have encountered an issue where a scope variable appears to be undefined when attempting to access it. Interestingly, upon printing out the scope, it is evident that the variable does indeed contain a value.

To further investigate this matter, please refer to your JavaScript console as that is where I have displayed this information.

For demonstration purposes, you can view a Plunker example here: http://plnkr.co/edit/1cSVZJgtlUazOqTuCNOK

javascript angularjs angularjs-directive

Answer 1

Answer №1

The reason for this issue is due to the <form> directive not being compiled before the compilation of the usernameAvailable directive, as it is a child scope of form. When you use console.log() to print the value, it actually displays the reference of the $scope object at that moment. To access the correct value, one workaround is to utilize $timeout().

Check out the DEMO here

app.directive('usernameAvailable', ['$http', '$q', '$timeout', function($http, $q, $timeout) {
  return {
    restrict: 'A',
    require: 'ngModel',
    scope: {
      usernameAvailable: '='
    },
    link: function(scope, elem, attr, controller) {
      $timeout(function() {
        scope.usernameAvailable.$asyncValidators.usernameAvailable = function(username) {
          if (typeof(getCurrentUsername) !== 'undefined' && username === getCurrentUsername()) {
            return $q.resolve();
          } else {
            return $http.get('/user/usernameAvailable?username=' + username).success(function(result) {
              if (result) {
                return $q.resolve();
              } else {
                return $q.reject();
              }
            });
          }
        };  
      });

    }
  }
}]);

Answer 2

The reason for this issue is due to the <form> directive not being compiled before the compilation of the usernameAvailable directive, as it is a child scope of form. When you use console.log() to print the value, it actually displays the reference of the $scope object at that moment. To access the correct value, one workaround is to utilize $timeout().

Check out the DEMO here

app.directive('usernameAvailable', ['$http', '$q', '$timeout', function($http, $q, $timeout) {
  return {
    restrict: 'A',
    require: 'ngModel',
    scope: {
      usernameAvailable: '='
    },
    link: function(scope, elem, attr, controller) {
      $timeout(function() {
        scope.usernameAvailable.$asyncValidators.usernameAvailable = function(username) {
          if (typeof(getCurrentUsername) !== 'undefined' && username === getCurrentUsername()) {
            return $q.resolve();
          } else {
            return $http.get('/user/usernameAvailable?username=' + username).success(function(result) {
              if (result) {
                return $q.resolve();
              } else {
                return $q.reject();
              }
            });
          }
        };  
      });

    }
  }
}]);

The worth of the scope is evident, yet it remains undefined when trying to access it

Answer №1

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