All code you write in Node will be wrapped in functions

Node wraps the Module code in a function, which we can inspect using the wrapper property of the Module Module. Exports is defined as a reference to Module.Exports prior to that. Require and Module are both specific to the function to be executed, and __Filename /_Dirname variables will contain the wrapped Module’s absolute Filename and directory path. This wrapper function has 5 arguments: exports, require, Module, __Filename,