This is the second time I've ended up reading this post, and I confess I still don't exactly understand what was going on here. There's an issue with PDFs missing their contents, but also timeouts and a missing method exception? The problem seems to have come from upgrading some dependencies at some point, but the solution is also an upgrade, as far as I can tell? And then the cache issues at the end sound very much like a red flag in terms of managing JS dependencies - as if they're trying to cache the node_modules directory in some way that isn't properly configured.

That said, the main sense I get is that the team aren't so experienced with Javascript, and therefore working with it is full of surprises because they just aren't used to it. I found the line about bugs in C code being "your fault" particularly amusing: having occasionally had to touch C and C++ code, I would have said the complete opposite! Javascript, for me, is very predictable - if something goes wrong, then it's usually because I made a clear mistake. But with C, I end up trying to debug chains of Makefile and CMake problems that have no rhyme or reason to them.

In other words: as someone inexperienced in C, it is a chaotic, magical language and ecosystem to me, in exactly the same way that the author describes Javascript being to them.

More practically, it sounds like the team need some regression tests for this case that they can run next time they try and upgrade their dependencies. They also need to make sure that caching is working properly for their Javascript code - rerunning the CI multiple times on the same commit should always produce exactly the same dependency tree every time. Probably that means caching the right directory and using NPM CI to clear and rebuild node_modules from scratch every time.

More generally, the author complains about a lack of type checks. In this case, it sounds like the missing method was somewhere in a dependency, so this may not have helped, but: Typescript! It exists, it adds types, it makes a lot of things easier. Easy mode Typescript is to just start writing `.ts` files and use the `tsx` package to automatically compile and execute everything - there are other approaches that they could explore, but this is probably the simplest.