Eslint validation with pre-commit

package.json

{
    "name": "example-app",
    "description": "Example package file for demonstrating pre-commit-eslint",
    "version": "0.0.1",
    "author": "Suhas Karanth",
    "repository": {
        "type": "git",
        "url": "git://github.com/suhas-karanth/example-app.git"
    },
    "engines": {
        "node": ">=6.3.0"
    },
    "scripts": {
        "eslint": "./pre-commit-eslint.sh",
        "test": "mocha -R spec"
    },
    "pre-commit": ["eslint", "test"],
    "devDependencies": {
        "eslint": "^3.1.1",
        "mocha": "*",
        "pre-commit": "^1.1.3"
    }
}

pre-commit-eslint.sh

#!/bin/bash

STAGED_FILES=$(git diff --cached --name-only --diff-filter=ACM | grep ".jsx\{0,1\}$")

if [[ "$STAGED_FILES" = "" ]]; then
  echo "Currently there are no files staged in git for validation."
  echo -e "Run 'git help add' for more on staging files for a commit.\n"
  exit 0
fi

GREEN='\033[32m'
RED_BG='\033[41m'
GREEN_BG='\033[42m'
NC='\033[0m'

PASS=true

echo -e "\nValidating Javascript with eslint:"

# Check for eslint
which eslint &> /dev/null
if [[ "$?" == 1 ]]; then
  echo -e "\t${RED_BG}Please install ESlint${NC}"
  exit 1
fi

for FILE in ${STAGED_FILES}
do
  eslint "$FILE"

  if [[ "$?" == 0 ]]; then
    echo -e "\t${GREEN}Passed: $FILE${NC}"
  else
    echo -e "\t${RED_BG}Failed: $FILE${NC}"
    PASS=false
  fi
done

echo -e "Javascript validation completed."

if ! ${PASS}; then
  echo -e "\n${RED_BG}ESlint validation failed!${NC} Fix the ESLint errors and try again. You can run ESLint validation manually via 'npm run eslint'."
  exit 1
else
  echo -e "\n${GREEN_BG}ESlint validation succeeded :)${NC}"
fi

exit $?

Usage.md

The test script and pre-commit-eslint.sh are triggered before commit. If there are any eslint validation errors or if any unit test fails, commit will fail:

suhas:~/workspace/node-dogstatsd$ git commit

Validating Javascript with eslint:

/home/suhas/workspace/node-dogstatsd/lib/statsd.js
  30:9  error  'x' is defined but never used  no-unused-vars

✖ 1 problem (1 error, 0 warnings)

	Failed: lib/statsd.js
	Passed: test/test_statsd.js

Javascript validation completed!

Eslint validation failed! Fix the ESLint errors and try again. You can run ESLint validation manually via 'npm run eslint'.
pre-commit: 
pre-commit: We've failed to pass the specified git pre-commit hooks as the `eslint`
pre-commit: hook returned an exit code (1). If you're feeling adventurous you can
pre-commit: skip the git pre-commit hooks by adding the following flags to your commit:
pre-commit: 
pre-commit:   git commit -n (or --no-verify)
pre-commit: 
pre-commit: This is ill-advised since the commit is broken.
pre-commit:

Make sure the script is executable chmod +x pre-commit-eslint.sh. The script was originally shared here