1. Indexing an array with 1 is unfortunate but not a bad design decision in a vacuum, eg for i=1,#size is a very easy to understand loop over valid array indexes. I'll agree that it causes cognitive load in practice.

2. JS has a somewhat broken notion of objects and Lua's implementation is far cleaner while being as powerful. How do you use a JavaScript object as a hashmap? The default try is a potential security hole.