Node Monorepo Githook Example

What is this?

This a an example of how you could use githooks and shell scripts to run pre-commit hooks in a monorepo containing TypeScript sub-projects running on Node.js.

Why?

When you want to run tests against your staged files before you can commit the files. This example:

• Only checks modified workspaces
• Skips unnecessary checks
• Checks the workspace types
• Lints staged files
• Formats staged files

If any of the tests fail it will immediately exit.

Similar projects

This offers similar functionality to these common packages:

• Husky
• Simple Git Hooks

and

• Lint-staged

But with zero dependencies

When might it be useful over those other packages?

• When you don't want extra dependencies in your codebase
• When you don't need all of their features
• When you can't install extra dependencies in your project
• When you want to use pre-commit githooks but your team doesn't

How to use

Prequisites

• Git v1.5.0+
• Unix or unix-like environment (tested with zsh on Mac 13 Ventura, Ubuntu 22.04 & Fedora 38)

Assumptions

• Using npm (you can easily modify this for yarn or pnpm)
• Workspace names match the name and case of the first level directory they are in
  

Both can be easily edited

Use locally without adding to the repo

1. Copy the pre-commit scripts
2. Edit pre-commit lines for your sub-projects e.g. 32 + 36
3. Rename each pre-commit-* file to match your workspace names
4. Edit each pre-commit-* file for your workspace name (line 3) and adjust tests for your needs
5. Make files executable e.g. chmod +x pre-commit*
6. Move files to .git/hooks in your project
7. Run git config --local core.hooksPath .git/hooks/ to initialise the githooks

• Note: any time you edit pre-commit you must re-run this for changes to take effect

Add to the repo and enable for everyone

1. Follow steps 1-5 above.
2. Choose the directory you'd like to store these scripts e.g. .githooks/
3. Update the workspace script paths in pre-commit
4. Edit your package.json adding a prepare script:

"scripts": {
  "prepare": "git config --local core.hooksPath .githooks/"
}

• Note: If using CI you will most likely not want to initialise these scripts. Take a look at the Husky guide for further advice.

5. Run the prepare script e.g. $ npm run prepare or just run $ npm i again

How do I opt out of the hooks?

Either:

• git commit --no-verify
  or
• git commit -n

Opt-in

Sometimes you don't want these checks to run by default

1. Edit pre-commit and uncomment lines 8-10
2. Default git commit behaviour will be unchanged and when you want to run the hooks

GIT_HOOKS=1 git commit

3. If you so choose, you could alias (git alias or shell alias) this to a shorter command

That's it!

DISCLAIMER:
While every effort has been made that this is correct, you should understand any scripts you run from the internet.
Use as your own risk.