Prepend commit message with JIRA issue ID

prepare-commit-msg

#!/usr/bin/env node

const fs = require('fs')
const { execSync } = require('child_process')

const msgFilePath = process.argv[2]
if (typeof msgFilePath !== 'string' && !msgFilePath.length) {
  console.error('Commit message file not passed in from Git!')
  process.exit(1)
}


const buffer = execSync(`git rev-parse --abbrev-ref HEAD`)
const currentBranch = buffer.toString().trim()

const re = /^(feature|hotfix|release|fix)(\/|-)(\w{2,4})-(\d+)$/

if (!re.test(currentBranch)) {
  // Unknown branch name format. Nothing to do here.
  process.exit(0)
}

const matches = currentBranch.match(re)

if (!matches) {
	process.exit(0)
}


const prefix = matches[3].toUpperCase()
const issueNumber = matches[4]
const issueID = `${prefix}-${issueNumber}`
const currentContent = fs.readFileSync(msgFilePath).toString()

// It's most likely an amended commit and is already prefixed with this issue ID.
// No need to append it again.
if (currentContent.startsWith(issueID)) {
  process.exit(0)
}

fs.writeFileSync(msgFilePath, issueID + ': ' + currentContent)