A husky hook to add `Change-Id` to commit messages

change-id.js

/*
  "husky": {
    "hooks": {
      "commit-msg": "node change-id.js -E HUSKY_GIT_PARAMS"
    }
  },
*/

const [,, arg, key] = process.argv

const { equal: assert } = require('assert').strict

assert(arg, '-E')
assert(key, 'HUSKY_GIT_PARAMS')

const filepath = process.env[key]

assert(filepath, '.git/COMMIT_EDITMSG')

const { existsSync: exists } = require('fs')
const { execSync: run } = require('child_process')

const gerrit = '.git/hooks/gerrit-commit-msg'

if (!exists(gerrit)) {
  const { repository: { url: remote } } = require(process.env.npm_package_json)
  const { URL } = require('url')
  const url = new URL(remote)
  const { port } = url
  assert(url.protocol, 'ssh:')
  url.port = ''
  url.pathname = ''
  const host = `${url}`.replace('ssh://', '')
  console.error('Downloading Gerrit `Change-Id` commit message hook')
  run(`scp -p -P ${port} ${host}:hooks/commit-msg ${gerrit}`)
}

run(`${gerrit} ${filepath}`)