calculate the total flight time (angular 6 function)

I would like this delivered today. I have a json file (loaded via a web service) where the flight times are all in local time, but the data needs to be adjusted for timezones. I would like a method such that my angular 6 code, can show the total flight time, including stop overs taking into account the time zone differences. For IPR reasons I cannot share the code. Total Flight Time. Start Time: FlightResultsList[]/FlightSegments[]/FlightSegmentLegs[MIN]/DepartDate + DepartTime (time zone from Source Location) End Time: FlightResultsList[]/FlightSegments[]/FlightSegmentLegs[MAX]/ArriveDate + ArriveTime (time zone from Destination Location) Each Segment FlightResultsList[]/FlightSegments[]/FlightSegmentLegs[]/DepartDate + DepartTime FlightResultsList[]/FlightSegments[]/FlightSegmentLegs[]/ArriveDate + ArriveTime The Maths would require; a lookup table/database including IATA airport and UTC [login to view URL] This is for an .angular 6 front end application For each flight I want to show the total flight time for the whole journey, and each segment. You can work on your own PC, I just require a method which will use the object (attached) as loaded, it is expected that the output will be shown to show that the flights and route is calculated correctly.