The Node.js execution context contains a few global variables and functions that can be used from anywhere in any script. The most widely used of all is the
require function, since it is the function that helps you load other modules and access the non-global functions, classes, and variables that are available from the Node.js APIs.
You must have noticed this function being used in the previous chapter when we loaded the
commander module from the package you installed in your application:
const program = require('commander');