How to programmatically add a guest attendee to GSuite calendar event on Save

I am building a GSuite Calendar extension.

My extension adds custom information to the description of the new event and needs to systematically add the same guest email e.g. test@mydomain.com.

I am able to inject into the description, but how can I add a guest programmatically without any user intervention?

Is there any way I can add that guest email using javascript? or use a post save tigger if any?

Any pointers?

from How to programmatically add a guest attendee to GSuite calendar event on Save