What book can I read to understand the correctness of writing and using classes?

Question

JavaScript

I ran into such a problem that I look at someone else's code and the modularity of the application is somehow more thought out in it.
Tell me, what book can I read, where, in addition to words, there will be more examples of how to properly structure and separate classes and other functionality? So that in the example the application from 0 to a full-fledged one would be assembled with an example code.

And there is something in terms of certain algorithms that many people almost never use if else, but instead they have other approaches.

Answer 1

https://refactoring.guru/