Reservation booking code samples

Question

I am putting together a couple code samples for prospective employers and would love some feedback. I am still pretty junior so I am not sure what constitutes a good code sample and the do's and dont's.

The code sample shows both the original version of the code which is currently in production (at my previous company), and a refactored version, which is not in production and untested.

// This code is part of a piece of functionality I wrote in which double-booking for reservations is handled
// on the front-end. There is a series of modals that fire to guide a user through the process and gives
// options to override a previous reservation, keep it, warns of any fee's, and proceeds to rebook if a user overrides.

// I used nested promises to manage the asynchronicity issues and prevent the modals from firing at the same time, 
// and to make sure they were firing in the proper order. Just below this you will find a recently refactored 
// version of this code (not in production) in which I separated the promises, and flattened the chain - making it 
// more readable, allowing for better error handling (if needed), and improving manageability. 

// ----------------- original (in production) ----------------------------------------- //

BookingHandler.handlePromise(Booking.book())
.catch(function BookingHandlerReject(data) {
    if (data.response.status === 412) {
        ChangeCancel.dblBookingFlow = true;

        //first promise
        ChangeCancel.userReservations().then(function(userReservations) {
            var reservations = userReservations.reservations; 
            var reservationId = data.response.data.specs.reservation_id;
            var venueName = data.response.data.venue.name;

            //second promise
            ChangeCancel.alertExistingReservation(venueName, reservationId, reservations).then(function() {
                ChangeCancel.rebook = true; 

                //third promise
                ChangeCancel.cancel().then(function() {
                    if (ChangeCancel.skipSecondModal) { 
                        book();
                        ChangeCancel.dblBookingFlow = false;
                        ChangeCancel.skipSecondModal = false;
                    } else if (!ChangeCancel.inChangeFlow) { 
                        if (ChangeCancel.continueWithRebooking) {
                            book();
                            ChangeCancel.isReplacingReservation = false;
                            ChangeCancel.dblBookingFlow = false;
                            ChangeCancel.skipSecondModal = false;
                        }
                    }
                });
            }); 
        });         
    } else {
        thisCtrl.messages.push('There was a problem while trying to book this reservation.');
        thisCtrl.messages.push(data.response.data.message);
    }
});




// ----------------- refactored (not in production) ----------------------------------------- //

BookingHandler.handlePromise(Booking.book())
.catch(function BookingHandlerReject(data) {    
    if(data.response.status === 412) {
        var alertConflictingReservation, 
            getUserReservations,
            overrideConflictingReservation; 

        ChangeCancel.dblBookingFlow = true;

        getUserReservations = function() {
            return ChangeCancel.userReservations().then(function(reservationsData){
                this.reservations = reservationsData;
                this.conflictingReservationId =  data.response.data.specs.reservation_id;
                this.conflictingVenueName = data.response.data.venue.name;

                return reservations;
            }, function(error){ $log.error(error); });
        }; 
        alertConflictingReservation = function() {
            ChangeCancel.rebook = true;
            return ChangeCancel.alertExistingReservation(this.conflictingVenueName, this.conflictingReservationId, this.reservations).then(function(alertData){
                return alertData;
            }, function(error){ $log.error(error); });
        };
        overrideConflictingReservation = function() {
            return ChangeCancel.cancel().then(function(overrideData) {  
                if (ChangeCancel.skipSecondModal) { 
                    book();
                    ChangeCancel.dblBookingFlow = false;
                    ChangeCancel.skipSecondModal = false;                   
                } else if (!ChangeCancel.inChangeFlow) { 
                    if (ChangeCancel.continueWithRebooking) {
                        book();
                        ChangeCancel.isReplacingReservation = false;
                    }
                }
                return overrideData;
            }, function(error){ $log.error(error); });
        }; 

        //call promise chain
        getUserReservations()
        .then(alertConflictingReservation)
        .then(overrideConflictingReservation);

    } else {
        thisCtrl.messages.push('There was a problem while trying to book this reservation.');
        thisCtrl.messages.push(data.response.data.message);     
    }
});

Answer 1

you have an oddly nested if statement that you can un-nest a little bit

    overrideConflictingReservation = function() {
        return ChangeCancel.cancel().then(function(overrideData) {  
            if (ChangeCancel.skipSecondModal) { 
                book();
                ChangeCancel.dblBookingFlow = false;
                ChangeCancel.skipSecondModal = false;                   
            } else if (!ChangeCancel.inChangeFlow) { 
                if (ChangeCancel.continueWithRebooking) {
                    book();
                    ChangeCancel.isReplacingReservation = false;
                }
            }
            return overrideData;
        }, function(error){ $log.error(error); });
    };

your else if condition could be added to so that you don't have to have another level of indentation in your code.

overrideConflictingReservation = function() {
    return ChangeCancel.cancel().then(function(overrideData) {  
        if (ChangeCancel.skipSecondModal) { 
            book();
            ChangeCancel.dblBookingFlow = false;
            ChangeCancel.skipSecondModal = false;                   
        } else if (!ChangeCancel.inChangeFlow && ChangeCancel.continueWithRebooking) {
            book();
            ChangeCancel.isReplacingReservation = false;
        }
        return overrideData;
    }, function(error){ $log.error(error); });
}; 

in the original it is the same way

//third promise
ChangeCancel.cancel().then(function() {
    if (ChangeCancel.skipSecondModal) { 
        book();
        ChangeCancel.dblBookingFlow = false;
        ChangeCancel.skipSecondModal = false;
    } else if (!ChangeCancel.inChangeFlow && ChangeCancel.continueWithRebooking) { 
        book();
        ChangeCancel.isReplacingReservation = false;
        ChangeCancel.dblBookingFlow = false;
        ChangeCancel.skipSecondModal = false; 
    }
});