The closure in question received an undefined Angular parameter

Question

The closure in question received an undefined Angular parameter

Here is something similar to what I have:

$scope.fetchData = function(path, save_to) {
    $http({method: 'GET', url: 'http://localhost:8001/www-root/' + path}).

         success(function(data, status, headers, config) {
             console.log("Success:  " + data);
             save_to = data;
         }).

         error(function(data, status, headers, config) {
             alert("Error: " + status);
         });
    });

When I use the function like this:

$scope.fetchData("get_users.pl", $scope.users);

The function retrieves the data from the server properly, but the $scope.users variable remains undefined. The question arises - why is that so?

javascript ajax angularjs

Answer 1

Answer №1

Instead of passing in the variable, just return the promise and handle it per-call:

$scope.getStructs = function (path) {
 return $http({
     method: 'GET',
     url: 'http://localhost:8001/www-root/' + path
 });
}

$scope.getStructs("get_users.pl").
 success(function (data, status, headers, config) {
     console.log("Success:  " + data);
     $scope.users = data;
 }).
 error(function (data, status, headers, config) {
     alert("Error: " + status);
 });

Edit:

It seems like you are looking to make this reusable by creating a factory that can be injected into any controller. Here's an example of how you can achieve that:

(function() {
  function StructFactory($http) {
    return {
      get: function(path) {
        return $http.get(path);
    }
  }
  angular.module('MyFactories', [])
         .factory('StructFactory', StructFactory);
})();

Include the module in your app module:

app = angular.module('myApp', ['MyFactories']);

Then include the factory in your controller:

(function() {
  function MyController($scope, StructFactory) {
    $scope.getStructs = function() {
      StructFactory.get('get_users.pl')
        .success(function(data) {
          $scope.users = data;
        })
        .error(function(data) {
          console.log('Error: ' + data);
        });
  }
  app.controller('MyController', MyController);
})();

Now you have the flexibility to use the factory in multiple controllers and easily add more methods as needed.

Answer 2

Instead of passing in the variable, just return the promise and handle it per-call:

$scope.getStructs = function (path) {
 return $http({
     method: 'GET',
     url: 'http://localhost:8001/www-root/' + path
 });
}

$scope.getStructs("get_users.pl").
 success(function (data, status, headers, config) {
     console.log("Success:  " + data);
     $scope.users = data;
 }).
 error(function (data, status, headers, config) {
     alert("Error: " + status);
 });

Edit:

It seems like you are looking to make this reusable by creating a factory that can be injected into any controller. Here's an example of how you can achieve that:

(function() {
  function StructFactory($http) {
    return {
      get: function(path) {
        return $http.get(path);
    }
  }
  angular.module('MyFactories', [])
         .factory('StructFactory', StructFactory);
})();

Include the module in your app module:

app = angular.module('myApp', ['MyFactories']);

Then include the factory in your controller:

(function() {
  function MyController($scope, StructFactory) {
    $scope.getStructs = function() {
      StructFactory.get('get_users.pl')
        .success(function(data) {
          $scope.users = data;
        })
        .error(function(data) {
          console.log('Error: ' + data);
        });
  }
  app.controller('MyController', MyController);
})();

Now you have the flexibility to use the factory in multiple controllers and easily add more methods as needed.

Answer 3

Answer №2

The reason for this behavior is that the argument being passed to the function is simply a reference to the original variable.

var x = 20;
function y(argument){
  argument++;
  console.log(argument);
}
// a temporary variable 'temp' is created with the value of `x`, then 'temp++' and 'console.log(temp)' are executed
y(x); //21
// the original variable `x` remains unchanged
console.log(x); //20

Answer 4

The reason for this behavior is that the argument being passed to the function is simply a reference to the original variable.

var x = 20;
function y(argument){
  argument++;
  console.log(argument);
}
// a temporary variable 'temp' is created with the value of `x`, then 'temp++' and 'console.log(temp)' are executed
y(x); //21
// the original variable `x` remains unchanged
console.log(x); //20

The closure in question received an undefined Angular parameter

Answer №1

Answer №2

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