How did I not find this earlier???

So this is basically a website that offers many terminals and online IDEs for dozens of programming languages, including stuff like Java, Python, C++, Assembly, Brainf**k, but also simple JS libraries such as p5 and processing.js (my current go-to libraries for when I want to do something funky with JS, such as program a game).

https://www.tutorialspoint.com/codingground.htm