changelog.js

#!/usr/bin/env node

const exec = require('child_process').exec
const path = require('path')
const moment = require('moment')
const prependFile = require('prepend-file')
const pkg = require('./package')

const version = pkg.version
const SEP = '##_'

exec(`git log --pretty=format:"%ad${SEP}%s${SEP}%h" --date=short version-${version}..HEAD`, (err, stdout, stderr) => {
  if (err) throw err
  if (stderr) throw new Error(stderr)
  const args = process.argv.slice(2)
  const version = args && args[0]
  if (!version) throw new Error('A version number must be provided')

  const location = _getChangelogLocation()
  const today = _getToday()
  const commits = _parseCommits(stdout)
  const message = _createMessage(version, today, commits)
  prependFile(location, message, err => {
    if (err) throw err
  })

  function _getChangelogLocation () {
    return path.resolve(__dirname, '..', 'changelog.md')
  }

  function _parseCommits (stdout) {
    return stdout
      .split('\n')
      .map(commit => {
        const chunks = commit.split(SEP)
        return {
          hash: chunks[2],
          date: chunks[0],
          message: {
            type: /(\w+)(\((\w+)\))?: (.*)/.exec(chunks[1])[1],
            package: /(\w+)(\((\w+)\))?: (.*)/.exec(chunks[1])[3],
            title: /(\w+)(\((\w+)\))?: (.*)/.exec(chunks[1])[4]
          }
        }
      })
  }

  function _getToday () {
    return moment().format('YYYY-MM-DD')
  }

  function _formatMessage (commit) {
    const commitPackage = commit.message.package
      ? ' ' + commit.message.package + ':'
      : ''
    return `*${commitPackage} ${commit.message.title} (${commit.hash})`
  }

  function _createMessage (version, date, commits) {
    const bugfixes = commits.filter(commit => ['fix', 'bugfix'].indexOf(commit.message.type) !== -1)
    const features = commits.filter(commit => ['feat'].indexOf(commit.message.type) !== -1)

    return `## ${version} (${date})

### Features
${features.map(_formatMessage).join('\n')}

### Bugs fixed
${bugfixes.map(_formatMessage).join('\n')}

`
  }
})