WorkAround project in CodeCademy intro to JavaScript

I am not having any issues with the WorkAround project, but having trouble understanding how payGrades can be used in workAround.js even though payGrades was not exported from employee.js. Is this just because the function uses the payGrades object in employee.js, processes it and workAround.js gets the result or is this wrong.
Link: https://www.codecademy.com/courses/introduction-to-javascript/projects/workaround
thanks

I believe you are correct. payGrades is an independent variable within Employee.js that the Employee functions access, then return within WorkAround.js

I have another question regarding this project . After moving every function into the object Employee, we have to check if each property is defined on Employee as per Step 6:

" For example, every instance of salary should be defined as Employee.salary since it is a property of the Employee object."

My question is, instead of defining ‘salary’ as Employee.salary, should we not use ‘this.salary’ ? isn’t this a better way of calling an objects property within itself ?