I don't think this is a problem you'll solve with books. To some extent code is a matter of taste, and good taste is more important than you'd think. You need

I don't think this is a problem you'll solve with books. To some extent code is a matter of taste, and good taste is more important than you'd think. You need to talk about each change and figure out what is driving it. Why was it wrong in that place when it was right yesterday. Figure out the general rules they are trying to follow and try not to make the same mistake twice. I know it's frustrating and demoralising but please view it as mentoring. In this industry, so many juniors never get the experience your getting and never learn how to code well. Please stop viewing changes as a personal failure. If you are getting many corrections you might want to slow down a bit. Properly test before committing and give the code a read through as if you were reviewing it. You don't say what kind of changes they are making. You need to figure out patterns there. If your senior is being an ass that's different. There are bullies in every walk of life. If that's the case try to keep them sweet. When I was younger and felt more experienced devs were getting at me, I often realise they meant well but were bad at communicating and particularly imagining the situation from my perspective on order to spot gaps in my knowledge. Ask them to pick out and talk you through how they would improve your code for an hour a week? In terms of avoiding getting people mad, mistakes are fine but repeat mistakes are not, so really focus on not needing the able correction twice.