Recursively ignore all files inside a specific directory except .json files

Question

I have a file structure similar to the one below:

foo/bar.foo
node_modules/foo/bar.json
node_modules/foo/bar/foo.bar

What I want to do is ignore all the files inside the node_modules folder except the json files so that I end up with the following file structure in my repo:

foo/bar.foo
node_modules/foo/bar.json

I tried to find a simple way to do that but I'm not quite there yet.

Here's what I came up with in my .gitignore:

# ignore everything inside node_modules
node_modules/*

# But descend into directories
!node_modules/**/*.json

What's the most elegant way to achieve the desired result?

P.S. I have no idea what I'm doing.

Answer 1

Ok so I finally found a solution. Here's what did the trick:

# Ignore all the files inside the node_modules folder
node_modules/**/*.*

# Allow only json files inside the node_modules folder
!node_modules/**/*.json

The issue was that by doing node_modules/*, it would not just ignore files but also folders.

And as the git doc says:

It is not possible to re-include a file if a parent directory of that file is excluded.

So instead I did node_modules/**/*.* which only exclude files and not folders.

That way, !node_modules/**/*.json is actually able to allow json files.