How to add some minutes to a Date format

So I’m working with the Google Calendar API and because the required date format I´m using the next way to get the starting time:

const date1 = (mail._doc.Data[1].Date + ‘T’ + mail._doc.Data[1].Time )
const startingTime = new Date (date1)

This works and give me the next input that allows me to create the event in the calendar if I manually set the ending time

2022-07-15T21:23:00.000Z

That starting time will change depending of data in the server. For the ending time I would like for it to be the starting time (whatever it is) plus 45 minutes but I cant make it work.

Any help would be appreciated.