What is your opinion on multiple classes per file?

and having the filename not the same as the class
names?

I prefer one per file, unless the other classes are trivial and local to the main class

1 per file.

Unless they're small extensions of the same class, then ok I guess.

Personally would like to keep it 1 class per file to keep things clean.

At most might initialise enums if the class isn't static in the same file

I'm in this codebase where 44 classes where per file.. I'm just one month at this new company and I kinda want to clean this.. but have no Idea how to start on this strange task

I'm okay with it. While some languages enforce the 1-to-1 relationship (e.g. Java), some don't and instead use files as a kind of module (e.g. Python, Kotlin).

In the end it's about understandability. If it helps to put multiple classes into a file, do it. If the file gets unwieldy, split it up.

Depends. I prefer one file per class but in Unity I often have a bunch of event definitions that vary only by argument types. I tend to throw those in a single file because use 4 lines per class tops.

In scala and ocaml, totally

In java, no

In rust, depends on the implementation

Don't be lazy, keep it clean for the next person.

It depends. For classes that differ greatly from each other, I think it's better to have them in separate files, but if you have a bunch of very short, very similar classes, it might be more helpful to group them in a single file.

For example, one of my Python projects has a bunch of Enum classes all in a single file, but larger classes with methods get their own files.

@r3nrut which is cleaner, 294 files, each with a 20 line class, or one file, with all the boilerplate classes grouped?

@yellow-dog 294 files is cleaner if there’s a proper project, module and package structure.

@yellow-dog from a change control or devops perspective it's a lot easier to understand and manage change/risk. If you have 20 small classes in a file and you forget something in the one-liner code change that breaks everything in that file of classes, is this a risk your stakeholders are okay with? However, there is an argument to be made that if the classes in that file are related and utilizing inheritance properly, if there's a mistake they all break anyway.

@r3nrut do you not have tests?

1 per file. It makes the git history cleaner, reusability easier and testing less unwieldy.

@yellow-dog yup but like Almond Sauce pointed out... I don't want to maintain the tests for a giant file which a bunch of tiny classes. It's just setting someone up for a headache that seems so simple to solve by using a file per class.