Motivation

node_modules often contains a lot of files that change frequently, which can significantly slow down backup solutions like Time Machine, so it would make sense to exclude them from backups.

How

Current Behaviour

node_modules folders are included in Time Machine backups

Desired Behaviour

Exclude node_modules from Time Machine backups using a "sticky exclusion". This can be done by adding the xattr com.apple.metadata:com_apple_backup_excludeItem to the node_modules folders with the value com.apple.backupd encoded as a binary plist:

00000000  62 70 6C 69 73 74 30 30 5F 10 11 63 6F 6D 2E 61  |bplist00_..com.a|
00000010  70 70 6C 65 2E 62 61 63 6B 75 70 64 08 00 00 00  |pple.backupd....|
00000020  00 00 00 01 01 00 00 00 00 00 00 00 01 00 00 00  |................|
00000030  00 00 00 00 00 00 00 00 00 00 00 00 1C           |.............|
0000003d

References

Rust already does this for their target folders: rust-lang/cargo#4386
My PR for implementing this for the poetry Python package manager: python-poetry/poetry#4599