GraphJS is event-driven. You can trigger certain functions at given hooks. Each method represented under the "Functions" tab in the navigation menu comes with a "after" and "before" hook.
For example, login comes with "beforeLogin" and "afterLogin" hooks. You may use them to trigger certain functions at specific times. Similarly showLogin has beforeShowLogin and afterShowLogin hooks.
You may bind a function to a hook by using GraphJS' on method. So, in order to trigger a console.log after logging in, you type in:
Please note, the "before" events may interrupt the progression of the call. The code block fired after the "before" event must finish with the goToNextStep(true); call. This ensures that the actual call gets executed.