The methods in AngularJS Factory are accessed through the returning object

Question

The methods in AngularJS Factory are accessed through the returning object

Trying to utilize the this keyword in an AngularJS factory can be a bit tricky. When you return an object with functions as properties and attempt to call one function from another using this, it may result in errors. Upon examining the this keyword through console.log, you may notice that it refers to the scope of the calling controller instead of the current returning object.

 app.module('admin').factory('login', [function() {
return {
    someFunc: function() {
        return 'abc'
    },
    anotherFunc : function(){

        var msg = this.someFunc();
        return 'Msg is '+ msg;

    },
    yetAnotherFunc : function(){

        var msg = this.someFunc();
        return 'Msg is '+ msg;

    }
}
}]).controller(['$scope', 'login', function($scope, login){
    login.someFunc(); // Works Fine
    login.anotherFunc(); // Error : this.someFunc is not a function
}])

javascript angularjs return this factory

Answer 1

Answer №1

Check out the solution on a fiddle:

https://jsfiddle.net/waxolunist/fcxu5eej/

Here is the HTML code:

<div ng-app="app">
    <div ng-controller="LoginController">
        Get a Message:
        <button ng-click="someFunc()">someFunc</button>
        <button ng-click="anotherFunc()">anotherFunc</button>
        <button ng-click="yetAnotherFunc()">yetAnotherFunc</button>

        <div>Answer: {{answer}}</div>
    </div>
</div>

JavaScript code:

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

app.controller('LoginController', function($scope, LoginFactory) {

    $scope.someFunc = function() {
        $scope.answer = LoginFactory.someFunc();
    }

    $scope.anotherFunc = function() {
        $scope.answer = LoginFactory.anotherFunc();
    }

    $scope.yetAnotherFunc = function() {
        $scope.answer = LoginFactory.yetAnotherFunc();
    }
});

app.factory('LoginFactory', [function() {
    return {
        someFunc: function() {
            return 'abc'
        },
        anotherFunc : function(){
            var msg = this.someFunc();
            return 'Msg is '+ msg;
        },
        yetAnotherFunc : function(){
            var msg = this.someFunc();
            return 'Another msg is '+ msg;
        }
    }
}]);

It may be worth considering using a service instead of a factory in your code. Nonetheless, your current implementation seems to be working fine.

Answer 2

Check out the solution on a fiddle:

https://jsfiddle.net/waxolunist/fcxu5eej/

Here is the HTML code:

<div ng-app="app">
    <div ng-controller="LoginController">
        Get a Message:
        <button ng-click="someFunc()">someFunc</button>
        <button ng-click="anotherFunc()">anotherFunc</button>
        <button ng-click="yetAnotherFunc()">yetAnotherFunc</button>

        <div>Answer: {{answer}}</div>
    </div>
</div>

JavaScript code:

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

app.controller('LoginController', function($scope, LoginFactory) {

    $scope.someFunc = function() {
        $scope.answer = LoginFactory.someFunc();
    }

    $scope.anotherFunc = function() {
        $scope.answer = LoginFactory.anotherFunc();
    }

    $scope.yetAnotherFunc = function() {
        $scope.answer = LoginFactory.yetAnotherFunc();
    }
});

app.factory('LoginFactory', [function() {
    return {
        someFunc: function() {
            return 'abc'
        },
        anotherFunc : function(){
            var msg = this.someFunc();
            return 'Msg is '+ msg;
        },
        yetAnotherFunc : function(){
            var msg = this.someFunc();
            return 'Another msg is '+ msg;
        }
    }
}]);

It may be worth considering using a service instead of a factory in your code. Nonetheless, your current implementation seems to be working fine.

Answer 3

Answer №2

Here is a suggestion:

app.module('admin').factory('login', [function() {
    function someFunc() {
        return 'abc';
    }

    return {
        someFunc: someFunc,
        anotherFunc : function(){

            var msg = someFunc();
            return 'Message is '+ msg;

        },
        yetAnotherFunc : function(){

            var msg = someFunc();
            return 'Message is '+ msg;

        }
    };
}]).controller(['$scope', 'login', function($scope, login){
    login.someFunc();
    login.anotherFunc();
}]);

Now the someFunc will be accessible within the returned object.

UPDATE:

Regarding the issue with using this, it seems like there might be a misunderstanding of how this operates in Javascript.

The usage of the this keyword typically functions as expected under these conditions:

You're calling a method on an object created with the new keyword
You're invoking a bound function (refer to the documentation)
You're executing a function through call or apply and supplying it with a context (this)

Upon analyzing Waxolunist's response, it appears that the provided code indeed functions correctly. Therefore, the error may stem from another source. It's possible that your implementation resembles something similar to this

$scope.yetAnotherFunc = login.yetAnotherFunc

This action detaches yetAnotherFunc from its context, which explains why this does not behave as anticipated.

Answer 4

Here is a suggestion:

app.module('admin').factory('login', [function() {
    function someFunc() {
        return 'abc';
    }

    return {
        someFunc: someFunc,
        anotherFunc : function(){

            var msg = someFunc();
            return 'Message is '+ msg;

        },
        yetAnotherFunc : function(){

            var msg = someFunc();
            return 'Message is '+ msg;

        }
    };
}]).controller(['$scope', 'login', function($scope, login){
    login.someFunc();
    login.anotherFunc();
}]);

Now the someFunc will be accessible within the returned object.

UPDATE:

Regarding the issue with using this, it seems like there might be a misunderstanding of how this operates in Javascript.

The usage of the this keyword typically functions as expected under these conditions:

You're calling a method on an object created with the new keyword
You're invoking a bound function (refer to the documentation)
You're executing a function through call or apply and supplying it with a context (this)

Upon analyzing Waxolunist's response, it appears that the provided code indeed functions correctly. Therefore, the error may stem from another source. It's possible that your implementation resembles something similar to this

$scope.yetAnotherFunc = login.yetAnotherFunc

This action detaches yetAnotherFunc from its context, which explains why this does not behave as anticipated.

Answer 5

Answer №3

Visit this link for the code

Here is a simple HTML code snippet:

<div ng-app="test" ng-controller="testController">
<input type="button" ng-click="testFunc2()" value="test2" />
<input type="button" ng-click="testFunc1()" value="test1" />
</div>

And this is the corresponding JS code:

var testModule = angular.module('test',[ ]);
testModule.controller('common' , function(  $scope ) {
$scope.testFunc1 = function(){
    alert("test1");
    };
});
testModule.controller('testController', function( $scope , $controller ){ 
//inherit
$controller('common', {
    $scope: $scope
});

$scope.testFunc2 = function (){
alert("test2");
};
});

If you prefer using controller with 'inherit', this approach might work for you.

Consider whether you really need to use 'Factory', as it may not be necessary in this context.

Answer 6

Visit this link for the code

Here is a simple HTML code snippet:

<div ng-app="test" ng-controller="testController">
<input type="button" ng-click="testFunc2()" value="test2" />
<input type="button" ng-click="testFunc1()" value="test1" />
</div>

And this is the corresponding JS code:

var testModule = angular.module('test',[ ]);
testModule.controller('common' , function(  $scope ) {
$scope.testFunc1 = function(){
    alert("test1");
    };
});
testModule.controller('testController', function( $scope , $controller ){ 
//inherit
$controller('common', {
    $scope: $scope
});

$scope.testFunc2 = function (){
alert("test2");
};
});

If you prefer using controller with 'inherit', this approach might work for you.

Consider whether you really need to use 'Factory', as it may not be necessary in this context.

The methods in AngularJS Factory are accessed through the returning object

Answer №1

Answer №2

Answer №3

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