如何返回JSON请求输入并在另一个函数中使用它？

I'm trying to set up an API login of sorts that when the login is successful, it returns an JWT and first/last name sent with the login from the POST request. My problem is that I cant figure out a way that works to return the first/last name variables to another Class and function. This my code:I'm trying to set up an API login of sorts that