A thing I discovered by myself when I was a teenager: do not update progress bars on every loop.

There's a lot of things front-end developers (be they web or graphical terminal) can learn from the game development world. I can recommend playing with e.g. Pico 8 sometime, it's artificially constrained so you have to work with the limitations instead of do the usual relatively naive work. It's LUA coding so it shouldn't be a problem for JS developers, assuming they don't mind working in a 20 column code editor (or thereabouts).

I think it’s more so important to get familiar with loop/event based programming. Most of my experience is in the request/response mindset of web requests so when I try out game dev, arduino dev, C# desktop apps, etc I find my mental model has to shift drastically

Loops occur so fast it’s pretty standard to have to put some throttling logic in the code which I’ve never had to do in web dev except perhaps the document.ready statement in JavaScript to make sure the dom has been loaded.

Games developers are not magically safe from the progress bar mistake.

Same here. I often implemented like this, where n was some reasonable value:

    if iteration % n === 0:
        update_progress()

I normally do it with a bitwise and of numbers that end with a sequence of 1s, like 7. so `i & 7 == 7`