update-changelog

#!/usr/bin/env node

const version = require('../package.json').version
const semver = require('semver')
const editor = require('editor')
const { readFileSync, writeFileSync, unlinkSync } = require('fs')
const { resolve } = require('path')

const template = (summary) => `
## ${version} (${datestamp()})

<!-- optional: if this is a significant release, describe it in a sentence or two -->

### Added
- Modify or remove as appropriate

### Changed
- Modify or remove as appropriate

### Deprecated
- Modify or remove as appropriate

### Removed
- Modify or remove as appropriate

### Fixed
- Modify or remove as appropriate

### Security
- Modify or remove as appropriate

`.trim()

const datestamp = () => (new Date().toISOString()).replace(/T.*$/, '')

const insert = (entry) => {
  const changelog = readFileSync(resolve(__dirname, '../CHANGELOG.md'), 'utf8')
  const replaced = changelog.replace(
    /(<!-- \{entry_placeholder\} -->)/,
    `$1\n\n${entry}`
  )
  writeFileSync(resolve(__dirname, '../CHANGELOG.md'), replaced, 'utf8')
}

const isUnstable = semver.prerelease(version) !== null
if (isUnstable) {
  console.log('skipping changelog update (prerelease versions don’t need changelogs)')
} else {
  const tmp = resolve(__dirname, '..', '.CHANGELOG_CURRENT_ENTRY.md')
  writeFileSync(tmp, template())
  editor(tmp, (code, sig) => {
    if (code !== 0) throw new Error('non-zero exit code from editor')
    insert(readFileSync(tmp))
    unlinkSync(tmp)
  })
}