How to extend Angular 2 HTTP Service with Factories

Recently I had an issue where I needed to add a JWT Token to the header of my API calls with Angular2 and with me practicing T-DRY, I had to figure out a way to do it.
I searched and searched and found almost nothing. I did however find a way to build a factory to do it and then noticed that there is hardly any documentation and hardly any resources about it. So I figured it would be helpful to others if I added it here.…