Angular: deferred var is undefined in then-method

Question

Within my Angular.JS code I'm calling the Yahoo YQL API with GET/JSONP and I do get a response. But there are two problems.

1. It calls the error method instead of success. Why?
2. The deferred variable seems to be undefined within the error-function. Why?

You can find the JsFiddle here. It is based on an AJAX example.

function DefaultCtrl($log, $scope, $http, myService) {

    var promise = myService.getSuggestions('yahoo');

    promise.then(
          function(payload) { 
              $log.info('receiving data', payload);
              $scope.test = payload;
              $log.info('received data', payload);
          },
          function(errorPayload) {
              $log.error('failure loading suggestions', errorPayload);
          });    
}

angular.module('MyModule', [])
.factory('myService', function ($http, $log, $q) {
    return {
        getSuggestions: function (symbol) {            

            var deferred = $q.defer();

            $http.jsonp("http://d.yimg.com/autoc.finance.yahoo.com/autoc", {
                cache: true,
                params: { 
                    callback: "YAHOO.Finance.SymbolSuggest.ssCallback",               
                    query: symbol
                }
            })
            .success(function(data) {
                deferred.resolve(data);
            })
            .error(function(msg, code) {
                $log.error("error");
                deferred.reject(msg);  // <---- error occurs here!
                $log.error(msg, code);
            });

            var YAHOO = window.YAHOO = {Finance: {SymbolSuggest: {}}};
            YAHOO.Finance.SymbolSuggest.ssCallback = function (data) {
                $log.info("received data", data);
            }; // YAHOO.Finance     

            return deferred.promise;
        }
    }
});

Answer 1

Here is a working example. You have to pass the callback function in the promise callback and then have your callback reject or resolve the promise. I think the problem with the code you posted is that, after the execution of your callback the success and error are both executed and as a result an undefined var was resolved/rejected.

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

myApp.controller('DefaultCtrl', function ($log, $scope, $http, myService) {

    var promise = myService.getSuggestions('yahoo');

    promise.then(

    function (payload) {
        $log.info('receiving data in DefaultCtrl', payload);
        $scope.test = payload;
    },

    function (errorPayload) {
        $log.error('failure loading suggestions', errorPayload);
    });

});


myApp.factory('myService', function ($http, $log, $q) {
    return {
        getSuggestions: function (symbol) {

            var YAHOO = window.YAHOO = {
                Finance: {
                    SymbolSuggest: {}
                }
            };
            YAHOO.Finance.SymbolSuggest.ssCallback = function (data) {
                $log.info("received data in ssCallback", data);
                deferred.resolve(data);
            }; // YAHOO.Finance     

            var deferred = $q.defer();

            $http.jsonp("http://d.yimg.com/autoc.finance.yahoo.com/autoc", {
                cache: true,
                params: { 
                    callback: "YAHOO.Finance.SymbolSuggest.ssCallback",               
                    query: symbol
                }
            })
            .then(YAHOO.Finance.SymbolSuggest.ssCallback);

            return deferred.promise;
        }
    }
});