TypeError: Cannot read property 'then' of undefined

Question

loginService.islogged() 

Above function return a string like "failed". However, when I try to run then function on it, it will return error of

TypeError: Cannot read property 'then' of undefined

and the cursor is indicate right after connected and before .then.

Below is the full function:

var connected=loginService.islogged();
alert(connected);
connected.then(function(msg){
    alert("connected value is "+connected);
    alert("msg.data value is "+msg.data);
    if(!msg.data.account_session || loginService.islogged()=="failed")       
        $location.path('/login');
});

UPDATE

Here is the islogged() function

islogged:function(){
    var cUid=sessionService.get('uid');
    alert("in loginServce, cuid is "+cUid);
    var $checkSessionServer=$http.post('data/check_session.php?cUid='+cUid);
    $checkSessionServer.then(function(){
        alert("session check returned!");
        console.log("checkSessionServer is "+$checkSessionServer);
        return $checkSessionServer;
    });
}

I am certain that the $checkSessionServer will result in a "failed" string. Nothing more.

Answer 1

You need to return your promise to the calling function.

islogged:function(){     var cUid=sessionService.get('uid');     alert("in loginServce, cuid is "+cUid);     var $checkSessionServer=$http.post('data/check_session.php?cUid='+cUid);     $checkSessionServer.then(function(){         alert("session check returned!");         console.log("checkSessionServer is "+$checkSessionServer);     });     return $checkSessionServer; // <-- return your promise to the calling function } 

Answer 2

TypeError: Cannot read property 'then' of undefined when calling a Django service using AngularJS.

If you are calling a Python service, the code will look like below:

this.updateTalentSupplier=function(supplierObj){   var promise = $http({     method: 'POST',       url: bbConfig.BWS+'updateTalentSupplier/',       data:supplierObj,       withCredentials: false,       contentType:'application/json',       dataType:'json'     });     return promise; //Promise is returned  } 

We are using MongoDB as the database(I know it doesn't matter. But if someone is searching with MongoDB + Python (Django) + AngularJS the result should come.