lint-commit-message.js

const fs = require('fs')

const reset = '\x1b[0m'
const red = '\x1b[31m'

const [messageFile] = process.env.HUSKY_GIT_PARAMS.split(' ')
const currentMessage = fs.readFileSync(messageFile, 'utf8').replace(/^# ------------------------ >8 ------------------------[\s\S]*$|^#.*\n/gm, '')

const errors = []

function check (message, cb) {
  if (cb(currentMessage)) {
    errors.push(message)
  }
}

check('Whitespace at beginning of message', m => /^\s/.test(m))
check('Title is too long. limit to 72 chars', m => m.trim().split(/\r?\n/, 1)[0].length > 72)
check('Title and body must be separated by a blank line', m => {
  const s = m.trim().split(/\r?\n/, 3)
  return s[1] != null && !!s[1].length
})

if (errors.length) {
  const s = errors.length > 1 ? 's' : ''
  console.log()
  console.log(red + `Error${s} in commit message:` + reset)
  errors.forEach(err => {
    console.log('  - ' + err)
  })
  console.log()
  console.log('-'.repeat(72))
  console.log('Original message:')
  console.log('='.repeat(72))
  console.log(currentMessage.trimRight())
  console.log('='.repeat(72))
  process.exit(1)
}