I don't know how log out in my app

My first page in my app is for login so… when user access, go to the main page. My code for navigate is like this:

this.navController.setRoot(Principal, {
param1: ‘usuario000’

My question is, if I’m in the main page and user want to log out and I need to go to the login page again how can I do that? Thanks in advance.

Best regards.