如何在Javascript中阻止函数在另一个函数外部调用？

I have a javascript function (function1) that checks some global variables (can the user connect, is the service available, etc) before calling another (legacy) function (function2) that actually pops a window and connects the user to our service. I want to prevent function2 from being called anywhere but from function1. Is this possible?I have a javascript function (function1) that c