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Pre-commit hook for eslint, linting *only* staged changes.
#!/bin/bash
for file in $(git diff --cached --name-only | grep -E '\.(js|jsx)$')
do
git show ":$file" | node_modules/.bin/eslint --stdin --stdin-filename "$file" # we only want to lint the staged changes, not any un-staged changes
if [ $? -ne 0 ]; then
echo "ESLint failed on staged file '$file'. Please check your code and try again. You can run ESLint manually via npm run eslint."
exit 1 # exit with failure status
fi
done
@gichuwil

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commented Sep 9, 2016

Thanks. Very helpful.

@Fer0x

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commented Jan 20, 2017

Option --diff-filter=d should be specified in git diff to exclude deleted files.

@alburritos

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commented Jan 28, 2017

@Fer0x Where would that go?

@rashtay

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commented Apr 24, 2017

@alberth8 It'd be like this -> git diff --diff-filter=d --cached --name-only

@gilesbutler

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commented May 30, 2017

Thanks @dahjelle! Great stuff :)

@solo474

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commented Aug 8, 2017

Thank you very much

@julianlam

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commented Aug 23, 2017

eslint is quite slow when it runs against my entire project, this is much faster, thanks!!

@SalTor

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commented Dec 19, 2017

Has anyone figured out a workflow for using the --fix flag during this pre-commit hook?

What I've come across is that when the pre-commit hook is triggered for files that are staged, the new changes aren't included in the commit.

It makes sense why it wouldn't be included: this is changing a staged file, and those changes would also have to be staged.

lint-staged has a partly-working fix for this, however, and as they note, this doesn't work for partially-staged files, AKA files whose changes have been cherry-picked for a commit.

@artem-litvinov

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commented Jan 30, 2018

@SalTor take a look at this. It works well for me.

@suyanhanx

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commented Apr 20, 2018

Thank you very much.

@jancimajek

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commented Apr 24, 2018

One-liner version of the above:

git diff --diff-filter=d --cached --name-only | grep -E '\.(js|jsx)$' | xargs -I % sh -c 'git show ":%" | eslint --stdin --stdin-filename "%";'
@richistron

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commented Apr 24, 2018

you can do this in one line git diff --cached --name-only | grep ".js$" | xargs ./node_modules/.bin/eslint

@Brantron

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commented Apr 25, 2018

nice, @richistron

@luuuis

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commented May 11, 2018

@jancimajek's one-liner is great but does not handle spaces (and other funny chars) in the filename. Using git diff -z with xargs -0 handles that nicely: luuuis/pre-commit.sh.

The @richistron one liner will lint the changed files in the local checkout, which is not necessarily what is being committed to Git if you have not staged every hunk in a file.

@TNT-Likely

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commented Sep 29, 2018

thanks

@sampathBlam

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commented Mar 14, 2019

Thanks @dahjelle.

@lifenstein

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commented Jul 4, 2019

The scripts above works well enough for a handful of changes, but for large projects when things like a project-wide search & replace is performed, it takes ages because the files are sent one by one to eslint. Running over the whole project only takes 20 seconds, but the commit hook takes 4 minutes! Is there a way to batch the files instead of calling eslint for every file one by one?

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