$httpBackend return promise value issue - angularjs

Question

I want to implement a login function using AngularJS and my backend is in Rails. i decided to implement it using the $httpBackend but I have a problem.
When it gets into the $httpBackend function, it does update the token with the latest token from the database but i need to return the value to my services of which that doesnt seem to be happening. I know this has to do with promise and deferred etc but i am not well conversant with those.
SO this is my code
var authorized = false;
var token;
$httpBackend.whenPOST('https://login').respond(function(method, url, data) {
var loginDetails = data;
var d= $q.defer();
function startToken(loginDetails) {
getTokens.newToken(loginDetails).then(function(result) {
if(result.length > 0) {
var updateDB = "UPDATE preferences SET value='"+result[0].token+"' WHERE description='token'";
$cordovaSQLite.execute(db, updateDB).then(function(res) {
var updateDB1 = "UPDATE preferences SET value='true' WHERE description='logged_in'";
$cordovaSQLite.execute(db, updateDB1).then(function(res) {
var query = "SELECT description, value FROM preferences";
$cordovaSQLite.execute(db, query).then(function(res) {
if(res.rows.length > 0) {
if(res.rows.item(3).value!=null || res.rows.item(3).value!='') {
getTokens.getCRMToken(res.rows.item(2).value).then(function(resulttoken){
if(resulttoken[0].token == res.rows.item(3).value) {
token = res.rows.item(3).value;
}
d.resolve(token)
});
}
} else {
console.log("No results found");
}
}, function (err) {
console.error(err);
});
}, function (err) {
console.error(err);
});
}, function (err) {
console.error(err);
});
}
else {
console.log("reject")
d.reject(result);
}
}, 1000);
return d.promise;
}
var a = startToken(loginDetails).then(function(token) {
// in here the value for token is correct i then go ahead to set the value for authorized and resolve it
console.log(token)
if(token.length > 0){
console.log("authorized true")
authorized = true;
d.resolve(token, authorized)
}
else
{
console.log("authorized false")
authorized = false;
d.reject(token, authorized)
}
return d.promise;
})
// this is where i have my issue. all i want to do is to just check if the value for authorized is true, if yes, return the value for token.
//authorized = true;
//return [200 , { authorizationToken: token }];
});

Answer 1

Complete rewrite
Sadly, I think the short answer is that you cannot use promises with $httpBackend. See this discussion: https://github.com/angular/angular.js/issues/11245
In my original answer, I didn't recognize that you were using the $httpBackend mock as I merely concentrated on your incorrect promise code. The information on promises (https://docs.angularjs.org/api/ng/service/$q) is still valid.
The unit test version of ngMock does not handle promises. If you are using a version of $httpBackend which can handle promises, you need to return the promise, not the [200, "status"].
However, that said, in your rewrite, you also reuse the same promise after it has been resolved which is incorrect. You can only resolve or reject a defer once. So you need to either chain your then() functions or create a new defer. Also, you didn't actually need to create a defer since the newToken() function actually returns a promise.