Using @TrameApp, how do I simply create an endpoint that returns a string?

Let’s say I have this simple @TrameApp:

@TrameApp()
class MyTrameApp:
    def __init__(self, server: Server = None):
        self.server = get_server(server)

def main():
    app = MyTrameApp()
    app.server.start()

if __name__ == "__main__":
    main()

How would I add an endpoint that returns the string Hello World as type text/plain?

How would I add an endpoint that returns the string console.log('Hello World'); as type application/javascript?

@Sebastien_Jourdain