run eslint only on changed (*.js files) files using pre-commit

package.json

{
  "scripts": {
    "eslint": "LIST=`git diff-index --name-only HEAD | grep .*\\.js | grep -v json`; if [ \"$LIST\" ]; then eslint $LIST; fi"
  },
  "devDependencies": {
    "pre-commit": "0.0.7",
    "eslint": "~0.5.1"
  },
  "pre-commit": [
    "eslint"
  ]
}

Mac osx terminal above shell script throws an error bellow works

{
  "scripts": {
    "eslint": "LIST=`git diff-index --name-only HEAD | grep -f *.js | grep -v json;`; if [ $LIST ]; then eslint $LIST; fi"
  },
  "devDependencies": {
    "pre-commit": "0.0.7",
    "eslint": "~0.5.1"
  },
  "pre-commit": [
    "eslint"
  ]
}

@saalmaan you should change 'grep -f .js' to 'grep .\.js', grep files is wrong.

I am getting this error :

grep: brackets ([ ]) not balanced

Any idea why ?

@hemikak https://unix.stackexchange.com/a/222856

When I run npm run eslint it doesn't do anything

When I run npm run eslint it doesn't do anything

@EddieOne do you have any modified/changed (according to Git) *.js files locally? If not, it won't (and shouldn't) do anything

Just adding to this thread

git diff-index --name-only HEAD | grep -E "(.*)\.(jsx|js)" | xargs node_modules/eslint/bin/eslint.js -c .eslintrc

A tiny thing: you might want to grep -E "(.*)\.(jsx|js)$"

This includes files that where deleted. Eslint obviously cannot check deleted files and therefor crashes. Is there a way to exclude these?

PS: Thx for this very useful snippet!

I found the solution, apparently you can exclude deleted filed using --diff-filter=d.
This gives us:

LIST=`git diff-index --name-only --diff-filter=d HEAD | grep .*\\.js | grep -v json`; if [ \"$LIST\" ]; then eslint --fix $LIST; fi

This works well enough if there are only a handful of files, but in a large project with hundreds if not thousands of files, a large merge commit can include a lot of ofiles. LIST is too big in this case - I'm getting ENAMETOOLONG error.

@grebenyuksv-preply I think it is great idea to run lint on all possible ext but I got this err
/bin/sh: 1: [: src/services/acc.js: unexpected operator
my setup "LIST=`git diff-index --name-only HEAD | grep -E \"(.*)\\.(jsx|js|scss)$\" | grep -v json;`; if [ $LIST ]; then eslint $LIST; fi"
You have any idea, Why I'm having this?

This worked for me on mac:

        "eslint": "LIST=`git diff-index --name-only --diff-filter=d HEAD | grep -E \"(.*)\\.(tsx|ts)\" | grep -v json`; if [ \"$LIST\" ]; then eslint $LIST --fix; fi",

Awesome dudes! Wont need lint-staged anymore

Problem here with using eslint --fix, is that the script is passing successfully, but the fixed file is now unstaged, and git is commiting the erronous change still unfixed. Can I reuse the list of staged files and git add them??