Exclude specific url from loading interceptor in AngularJS [duplicate] - angularjs

Question

In the documentation (version 1.1) of AngularJS about interceptors, the interceptor functions all return something like this
return response || $q.when(response);
However, in my app, 'response' is always defined, so $q.when(response) is never executed.
So the question is in what situation will the 'response' be undefined and what will
$q.when(response) // == $q.when(null)
do! because response is undefined/null ?

Answer 1

$q.when(promise) → promise
$q.when(nonPromise) → a new promise, that will asynchronously resolve to the given value nonPromise.
Lets see what is $q.when:
$q.when = function (foreignPromise) {
var deferred = $q.defer();
foreignPromise.then(function (data) {
deferred.resolve(data);
$rootScope.$digest();
}, function (reason) {
deferred.reject(reason);
$rootScope.$digest();
});
return deferred.promise;
}
Factory return $q.when(data)
As we can see $q.when receives promise or nonPromise and wrap it with.
Factory example:
fessmodule.factory('Data', ['$resource','$q', function($resource, $q) {
var data = [
{
"PreAlertInventory": "5.000000",
"SharesInInventory": "3.000000",
"TotalSharesSold": "2.000000",
"TotalMoneySharesSold": "18.000000",
"TotalSharesBought": "0.000000",
"TotalShareCost": "0.000000",
"EstimatedLosses": "0.000000"
}
];
var factory = {
query: function (selectedSubject) {
return $q.when(data);
}
}
return factory;
}]);
Now we can call it from controller:
Data.query()
.then(function (result) {
$scope.data = result;
}, function (result) {
alert("Error: No data returned");
});
Demo Fiddle
Factory returns $q.when(data) || data
From this example we return promise. So lets change it a bit:
Instead return $q.when(data); we will write:
return $q.when(data) || data;
It will work as well. But not vice versa.
As I understand Angular knows that controller waits from Data service the promise and above mentioned statement will use 1st off $q.when(data).
Demo 2 Fiddle
Factory returns data || $q.when(data)
Now lets call our Data service by this way:
$scope.data = Data.query();
No promises, the call is sync.
Out factory seems like:
fessmodule.factory('Data', ['$resource','$q', function($resource, $q) {
var data = [
{
"PreAlertInventory": "5.000000",
"SharesInInventory": "3.000000",
"TotalSharesSold": "2.000000",
"TotalMoneySharesSold": "18.000000",
"TotalSharesBought": "0.000000",
"TotalShareCost": "0.000000",
"EstimatedLosses": "0.000000"
}
];
var factory = {
query: function (selectedSubject) {
return data || $q.when(data);
}
}
return factory;
}]);
Demo 3 Fiddle
My Conclusion
The return data || $q.when(data) means that our service can return single value or promise. But since we know what type of data our service returns , there is no sense in this statement. Or data or promise.

Answer 2

The statements:
return config || $q.when(config);
//AND
return response || $q.when(response);
Are shown in V1.1 of the Documentation of interceptors. It was removed from later versions of the documentation. I think it was a misguided attempt to document that interceptor functions can return either a value or a promise.
The statements otherwise make no sense as config and response always have a reference.