Nested $promise undefined error - angularjs

Question

I am getting the error Cannot read property of '$promise' of undefined.
Here is the code that is throwing it:
var myPromise = sharedDataService.getData($scope.entityId).$promise;
resolvePromise(myPromise, 'entityData');
the resolvePromise method:
function resolvePromise(promise, resultObject){
promise.then(function(response){
$scope[resultObject] = result;
});
promise['catch'](function(error){
//error callback
});
promise['finally'](function(){
//finally callback
});
sharedDataService looks like this:
var publicInterface = {
getData: getData
};
var storedData;
function getData(entityId) {
if(storedData.entityId === entityId){
return storedData;
}else{
var entityDataPromise = dataAccessService.getEntityData(entityId).$promise;
entityDataPromise.then(function (response) {
storedData = response;
return storedData ;
});
entityDataPromise['catch'](function(error) {
//throw error;
});
entityDataPromise['finally'](function(done) {
//do finally
});
}
}
return publicInterface;
finally, the dataAccessService:
var publicInterface = {
getEntityData: getEntityData
}
var entityData = $resource(apiUrl + 'Entity', {}, {
'getEntityData': {
method: 'GET',
url: apiUrl + 'Entity/getEntityDataById'
}
}
function getEntityData(entityId){
return entityData.getEntityData({entityId: entityId})
}
return publicInterface;
the original promise is throwing an error. When I put breakpoints various places, I can see my data is being returned sometimes. The functionality of sharedDataService is almost one of a chaching service.
Why is my original promise returning undefined?

Answer 1

Your getData() method doesn't have a return when if is false. So you would need to return entitiyDataPromise.
But, that would mean one condition returns a promise and the other returns an object
So both conditions need to return a promise and we can use $q for the first condition
function getData(entityId) {
if(storedData.entityId === entityId){
// return to getData()
return $q.resolve(storedData);
}else{
var entityDataPromise = dataAccessService.getEntityData(entityId).$promise;
// return to getData()
return entityDataPromise.then(function (response) {
storedData = response;
return storedData ;
});
entityDataPromise['catch'](function(error) {
//throw error;
});
entityDataPromise['finally'](function(done) {
//do finally
});
}
}
Be sure to inject $q in service.
In controller would be:
var myPromise = sharedDataService.getData($scope.entityId);
resolvePromise(myPromise, 'entityData');