There are a lot of gatcha moments in JS with weird behavior that makes it really easy to shoot yourself in the foot. It does get better as you get more experience but a lot of the oddities probably shouldn’t have existed to begin with. For what it was originally intended for (adding light scripting to websites) it’s fine but it very quickly gets out of hand the more you try to scale it up to larger codebases. TypeScript helps a little bit but the existence (and common usage) of ‘any’ has the potential to completely ruin any type safety guarantees TypeScript is intended to provide.