What's the best way to learn a new big project without a wiki?

Question

JavaScript

Good afternoon!
I have been doing front-end for a long time, but recently I had to take on a fairly large project running under node.js. I got this project without any documentation and wiki, and therefore I have to study it in the course of fixing bugs and adding features, which ultimately results in crutches and not very beautiful solutions due to a lack of understanding of its architecture as a whole.
Maybe I'm wrong, and is there some more correct approach in studying someone else's architecture without documentation? I hope that more experienced programmers will be able to share their experience and suggest better ways.

Answer 1

Yes, there is such a tool - find the one who wrote it, put it next to you and write the code. It's a bit like pair programming, except you have to wear a bicycle or motorcycle helmet on your head.

Answer 2

You need to write tests
At least acceptance (functional)
Then cover with unit tests
Then it will only get worse
When there are tests, you can shit code, and then refactor