Lint-staged: Multiple Package.json files

[awebdeveloper]

Does this support multiple package.json files. I have 2 folders API and UI both have their own package.json. Does lint-staged support that.

[sudo-suhas]

Yes it does. You configure lint-staged as you normally would if the git directory and the project root were the same.

Consider a project with the following file structure:

|-- .git
`-- packages
    |-- prj-1
    |   |-- .eslintrc.yml
    |   |-- .gitignore
    |   |-- .lintstagedrc.yml <- here's the config file
    |   |-- package.json
    |   |-- src
    |   |   `-- index.js
    |   `-- yarn.lock
    `-- prj-2
        `-- file

lint-staged can be setup for prj-1 with the following config:

.lintstaged.yml

linters:
  src/*.js:
    - eslint --fix
    - git add

[awebdeveloper]

cool. I didn't find a mention of this in the docs. I may have missed it. If i have not, can this be updated.

[sudo-suhas]

You are quite right. Actually, before lint-staged@5 release, you would have had to configure the gitDir for your project and specify the globs relative to the git root. I have created a PR which adds the relevant documentation to the readme. Thank you.

[awebdeveloper]

just clarifying. Say i have 2 folders each with it's own package.json. If i commit a code in folder A it triggers package.json of folder A. If i commit a code in folder b it triggers a package.json in folder b ??

[sudo-suhas]

I had not tested this myself. While lint-staged works for multi package projects, husky, which is used to setup the pre-commit hooks, doesn't. There is a PR open for this though - typicode/husky#13 and some relevant discussion in typicode/husky#160.

[sudo-suhas]

@awebdeveloper Also see typicode/husky:docs.md@dev#multi-package-repository-monorepo. However, this documentation is for the beta version and I am not completely sure how this can be used with lint-staged + lerna. I might try this out later today if I get some time.

[sudo-suhas]

Hey @awebdeveloper I have created a repo which demonstrates use of lint-staged in a multi package monorepo with lerna and husky - https://github.com/sudo-suhas/lint-staged-multi-pkg. Hope it helps.

[awebdeveloper]

thanks @sudo-suhas for everything. Much appreciated. Is Lerna really needed

[sudo-suhas]

If you try to install husky in each package, the last package in which you installed it, is the only one for which the pre-commit hook will be run. Which is why you need to install husky in the root folder. After that, you could configure lint-staged from the root folder with a config which might look like this:

linters:
  prj-1/src/*.js:
    - eslint --fix
    - git add
  prj-2/lib/*.js:
    - eslint --fix
    - git add

This also means that you have to install eslint, or any other linters you want to use, in the root package.

If you want to configure lint-staged for each package, you need a way to execute the precommit script for each package. This is where lerna comes in. While you may not _need_ it, it makes your job easier.