Yeah they would be much better off importing a few npm packages for that, and setting up some CI to build this with webpack and deploy to serverless /s Nothing

Yeah they would be much better off importing a few npm packages for that, and setting up some CI to build this with webpack and deploy to serverless /s Nothing wrong with the code per se - a little formatting and nicer variable names would make it entirely readable. Having the entire logic inline might be intentional so you can cross-check (legal) requirements and avoid transitive dependencies - the handling of dates specified might not necessarily match what’s “technically correct” at all times. Anyone writing Go will be familiar with this style.