feat: prepend the CHANGELOG file instead of rewriting it

Author: lekterable

CHANGELOG.md

@@ -1,3 +1,7 @@
+## Latest
+
+- feat: add update version feature fdef971e
+
 ## 0.2.0
 
 - feat: include changelog in the releases 2da21c56

src/index.js

@@ -3,18 +3,23 @@ import semver from 'semver'
 import {
   commitRelease,
   generateLine,
+  generateReleased,
   getCommitDetails,
   getCommits,
+  getLatestTag,
   updateVersion
 } from './utils'
 
 export const changelog = async (version, options) => {
   const title = version || 'Latest'
-  const commits = await getCommits()
+  const latestTag = await getLatestTag()
+  const commits = await getCommits(latestTag)
   const latestCommit = getCommitDetails(commits[0])
   const isReleaseLatest = latestCommit.scope === 'release'
   let changelog = isReleaseLatest ? '' : `## ${title}\n\n`
 
+  const released = latestTag && (await generateReleased(latestTag))
+
   commits.forEach((commit, index) => {
     const commitDetails = getCommitDetails(commit)
     const nextCommit = getCommitDetails(commits[index + 1])
@@ -24,9 +29,11 @@ export const changelog = async (version, options) => {
     if (line) changelog += line
   })
 
-  return options && options.write
-    ? writeFileSync('CHANGELOG.md', changelog)
-    : process.stdout.write(changelog)
+  if (!options || !options.write) return process.stdout.write(changelog)
+
+  const newChangelog = released ? changelog + '\n' + released : changelog
+
+  return writeFileSync('CHANGELOG.md', newChangelog)
 }
 
 export const release = async version => {

src/utils/index.js

@@ -1,4 +1,5 @@
 import { exec } from 'child_process'
+import { readFile } from 'fs'
 
 const execAsync = command =>
   new Promise((resolve, reject) =>
@@ -14,12 +15,54 @@ export const commitRelease = async version => {
   await execAsync(`git tag ${version}`)
 }
 
-export const getCommits = async () => {
-  const commits = await execAsync('git log --format="%H %s"')
+export const getCommits = async tag => {
+  const query = tag
+    ? `git log --format="%H %s" ${tag}..`
+    : 'git log --format="%H %s"'
+  const commits = await execAsync(query)
 
   return commits.split('\n').filter(commit => commit)
 }
 
+export const generateReleased = previousVersion =>
+  new Promise((resolve, reject) =>
+    readFile('CHANGELOG.md', 'utf8', (err, data) => {
+      if (err) return reject(err)
+
+      let isLatest = false
+      const released = data
+        .split('\n')
+        .filter(line => {
+          if (line === '## Latest') {
+            isLatest = true
+
+            return false
+          }
+
+          if (isLatest && line === `## ${previousVersion}`) {
+            isLatest = false
+
+            return true
+          }
+
+          return !isLatest
+        })
+        .join('\n')
+
+      if (isLatest) {
+        return reject(new Error('Previous release not found in CHANGELOG'))
+      }
+
+      return resolve(released)
+    })
+  )
+
+export const getLatestTag = async () => {
+  const latestTag = await execAsync('git tag | tail -n 1')
+
+  return latestTag ? latestTag.replace('\n', '') : null
+}
+
 export const getCommitDetails = commit => {
   if (!commit) return null
 

src/utils/index.test.js

@@ -1,15 +1,21 @@
 import { exec } from 'child_process'
+import { readFile } from 'fs'
 import {
   commitRelease,
   generateLine,
+  generateReleased,
   getCommitDetails,
   getCommits,
+  getLatestTag,
   updateVersion
 } from './index'
 
 jest.mock('child_process', () => ({
   exec: jest.fn()
 }))
+jest.mock('fs', () => ({
+  readFile: jest.fn()
+}))
 
 describe('utils', () => {
   beforeEach(() => jest.resetAllMocks())
@@ -33,6 +39,26 @@ describe('utils', () => {
     })
   })
 
+  describe('getLatestTag', () => {
+    it('should return null if there is no tag', async () => {
+      exec.mockImplementation((_, cb) => cb(null))
+      const latestTag = await getLatestTag()
+
+      expect(latestTag).toBe(null)
+      expect(exec).toBeCalledTimes(1)
+      expect(exec).toBeCalledWith('git tag | tail -n 1', expect.any(Function))
+    })
+
+    it('should return latest tag', async () => {
+      exec.mockImplementation((_, cb) => cb(null, '2.2.2'))
+      const latestTag = await getLatestTag()
+
+      expect(latestTag).toBe('2.2.2')
+      expect(exec).toBeCalledTimes(1)
+      expect(exec).toBeCalledWith('git tag | tail -n 1', expect.any(Function))
+    })
+  })
+
   describe('getCommits', () => {
     it('should reject if receives an error', async () => {
       const error = 'error'
@@ -62,6 +88,28 @@ describe('utils', () => {
       )
       expect(commits).toEqual(mockedOutput)
     })
+
+    it('should return commits since tag', async () => {
+      const mockedInput =
+        'bffc2f9e8da1c7ac133689bc9cd14494f3be08e3 refactor: extract line generating logic to function and promisify exec\naa805ce71ee103965ce3db46d4f6ed2658efd08d feat: add option to write to local CHANGELOG file\nf2191200bf7b6e5eec3d61fcef9eb756e0129cfb chore(release): 0.1.0\nb2f5901922505efbfb6dd684252e8df0cdffeeb2 fix: support other conventions\n4e02179cae1234d7083036024080a3f25fcb52c2 feat: add execute release feature'
+      const mockedOutput = [
+        'bffc2f9e8da1c7ac133689bc9cd14494f3be08e3 refactor: extract line generating logic to function and promisify exec',
+        'aa805ce71ee103965ce3db46d4f6ed2658efd08d feat: add option to write to local CHANGELOG file',
+        'f2191200bf7b6e5eec3d61fcef9eb756e0129cfb chore(release): 0.1.0',
+        'b2f5901922505efbfb6dd684252e8df0cdffeeb2 fix: support other conventions',
+        '4e02179cae1234d7083036024080a3f25fcb52c2 feat: add execute release feature'
+      ]
+
+      exec.mockImplementation((_, cb) => cb(null, mockedInput))
+      const commits = await getCommits('2.2.2')
+
+      expect(exec).toBeCalledTimes(1)
+      expect(exec).toBeCalledWith(
+        'git log --format="%H %s" 2.2.2..',
+        expect.any(Function)
+      )
+      expect(commits).toEqual(mockedOutput)
+    })
   })
 
   describe('getCommitDetails', () => {
@@ -90,6 +138,34 @@ describe('utils', () => {
     })
   })
 
+  describe('generateReleased', () => {
+    it('should reject if receives an error', async () => {
+      const error = 'error'
+      readFile.mockImplementation((_, __, cb) => cb(error))
+
+      expect(generateReleased()).rejects.toMatch(error)
+    })
+
+    it('should reject if there is no released but tag provided', async () => {
+      const error = 'Previous release not found in CHANGELOG'
+      const mockedInput =
+        '## Latest\n- feat: include changelog in the releases 2da21c56\n- test: add utils tests 217b25d0'
+      readFile.mockImplementation((_, __, cb) => cb(null, mockedInput))
+
+      expect(generateReleased('2.2.2')).rejects.toThrow(error)
+    })
+
+    it('should generate released', async () => {
+      const mockedInput =
+        '## Latest\n- feat: include changelog in the releases 2da21c56\n- test: add utils tests 217b25d0\n## 2.2.2\n- feat: add feature 2da21c56'
+      const mockedOutput = '## 2.2.2\n- feat: add feature 2da21c56'
+      readFile.mockImplementation((_, __, cb) => cb(null, mockedInput))
+      const released = await generateReleased('2.2.2')
+
+      expect(released).toBe(mockedOutput)
+    })
+  })
+
   describe('generateLine', () => {
     it('should generate release line', () => {
       const mockedInput = {