BREAKING: Format changelog using Prettier (#100)

Author: Mrtenz

jest.config.cjs

@@ -6,13 +6,13 @@
 /**
  * Dependencies that are ESM-only, and need to be transpiled by Babel.
  * This list is used in the `transformIgnorePatterns` option below.
- * 
+ *
  * You probably need to add a dependency to this list if the tests fail with something like:
  * - `SyntaxError: Cannot use import statement outside a module`
  * - `SyntaxError: Unexpected token 'export'`
  * If so, identify the dependency that's causing the error via the stack trace, and add it
  * to this list.
- * 
+ *
  * No, we do not live in the best of all possible worlds. Why do you ask?
  *
  * For details on Jest's currently experimental ESM support see: https://github.com/jestjs/jest/issues/9430

package.json

@@ -50,6 +50,7 @@
     "@types/jest": "^29.5.10",
     "@types/jest-when": "^3.5.2",
     "@types/node": "^17.0.23",
+    "@types/prettier": "^2.7.3",
     "@types/rimraf": "^4.0.5",
     "@types/which": "^3.0.0",
     "@types/yargs": "^17.0.10",
@@ -75,6 +76,9 @@
     "tsx": "^4.6.1",
     "typescript": "~5.1.6"
   },
+  "peerDependencies": {
+    "prettier": "^2"
+  },
   "packageManager": "[email protected]",
   "engines": {
     "node": "^16.20 || ^18.16 || >=20"

src/functional.test.ts

@@ -302,7 +302,9 @@ describe('create-release-branch (functional)', () => {
               ## [Unreleased]
 
               ## [2.0.0]
+
               ### Uncategorized
+
               - Update "a"
               - Initial commit
 
@@ -317,7 +319,9 @@ describe('create-release-branch (functional)', () => {
               ## [Unreleased]
 
               ## [2.0.0]
+
               ### Uncategorized
+
               - Initial commit
 
               [Unreleased]: https://github.com/example-org/example-repo/compare/@scope/[email protected]
@@ -362,7 +366,9 @@ describe('create-release-branch (functional)', () => {
             ## [Unreleased]
 
             ## [1.0.0]
+
             ### Added
+
             - Initial release
 
             [Unreleased]: https://github.com/example-org/example-repo/compare/@scope/[email protected]
@@ -376,7 +382,9 @@ describe('create-release-branch (functional)', () => {
             ## [Unreleased]
 
             ## [1.0.0]
+
             ### Added
+
             - Initial release
 
             [Unreleased]: https://github.com/example-org/example-repo/compare/@scope/[email protected]
@@ -413,11 +421,15 @@ describe('create-release-branch (functional)', () => {
               ## [Unreleased]
 
               ## [2.0.0]
+
               ### Uncategorized
+
               - Update "a"
 
               ## [1.0.0]
+
               ### Added
+
               - Initial release
 
               [Unreleased]: https://github.com/example-org/example-repo/compare/@scope/[email protected]
@@ -432,7 +444,9 @@ describe('create-release-branch (functional)', () => {
             ## [Unreleased]
 
             ## [1.0.0]
+
             ### Added
+
             - Initial release
 
             [Unreleased]: https://github.com/example-org/example-repo/compare/@scope/[email protected]
@@ -486,7 +500,9 @@ describe('create-release-branch (functional)', () => {
               ## [Unreleased]
 
               ## [1.0.0]
+
               ### Added
+
               - Initial release
 
               [Unreleased]: https://github.com/example-org/example-repo/compare/@scope/[email protected]
@@ -522,7 +538,9 @@ describe('create-release-branch (functional)', () => {
               ## [Unreleased]
 
               ## [1.0.0]
+
               ### Uncategorized
+
               - Update "a"
 
               [Unreleased]: https://github.com/example-org/example-repo/compare/@scope/[email protected]
@@ -536,7 +554,9 @@ describe('create-release-branch (functional)', () => {
               ## [Unreleased]
 
               ## [1.0.0]
+
               ### Added
+
               - Initial release
 
               [Unreleased]: https://github.com/example-org/example-repo/compare/@scope/[email protected]
@@ -773,7 +793,9 @@ describe('create-release-branch (functional)', () => {
               ## [Unreleased]
 
               ## [2.0.0]
+
               ### Uncategorized
+
               - Update "a"
               - Initial commit
 

src/package.test.ts

@@ -12,6 +12,7 @@ import {
   createNoopWriteStream,
 } from '../tests/unit/helpers.js';
 import {
+  formatChangelog,
   readMonorepoRootPackage,
   readMonorepoWorkspacePackage,
   updatePackage,
@@ -494,11 +495,15 @@ describe('package', () => {
             ## [Unreleased]
 
             ## [2.0.0]
+
             ### Uncategorized
+
             - Add isNewFunction ([#2](https://repo.url/compare/package/pull/2))
 
             ## [1.0.0] - 2020-01-01
+
             ### Changed
+
             - Something else
 
             [Unreleased]: https://repo.url/compare/[email protected]
@@ -572,6 +577,7 @@ describe('package', () => {
             projectRootDirectory: sandbox.directoryPath,
             repoUrl: 'https://repo.url',
             tagPrefixes: ['package@', 'v'],
+            formatter: formatChangelog,
           })
           .mockResolvedValue('new changelog');
         await fs.promises.writeFile(changelogPath, 'existing changelog');
@@ -610,6 +616,7 @@ describe('package', () => {
             projectRootDirectory: sandbox.directoryPath,
             repoUrl: 'https://repo.url',
             tagPrefixes: ['package@', 'v'],
+            formatter: formatChangelog,
           })
           .mockResolvedValue(undefined);
         await fs.promises.writeFile(changelogPath, 'existing changelog');
@@ -673,4 +680,30 @@ describe('package', () => {
       });
     });
   });
+
+  describe('formatChangelog', () => {
+    it('formats a changelog', () => {
+      const unformattedChangelog = `#  Changelog
+##     1.0.0
+
+ - Some change
+## 0.0.1
+
+- Some other change
+`;
+
+      expect(formatChangelog(unformattedChangelog)).toMatchInlineSnapshot(`
+        "# Changelog
+
+        ## 1.0.0
+
+        - Some change
+
+        ## 0.0.1
+
+        - Some other change
+        "
+      `);
+    });
+  });
 });

src/package.ts

@@ -2,6 +2,7 @@ import fs, { WriteStream } from 'fs';
 import path from 'path';
 import { format } from 'util';
 import { parseChangelog, updateChangelog } from '@metamask/auto-changelog';
+import prettier from 'prettier';
 import { WriteStreamLike, readFile, writeFile, writeJsonFile } from './fs.js';
 import { isErrorWithCode } from './misc-utils.js';
 import {
@@ -272,13 +273,25 @@ export async function migrateUnreleasedChangelogChangesToRelease({
     changelogContent,
     repoUrl: repositoryUrl,
     tagPrefix: `${pkg.validatedManifest.name}@`,
+    formatter: formatChangelog,
   });
 
   changelog.addRelease({ version });
   changelog.migrateUnreleasedChangesToRelease(version);
   await writeFile(pkg.changelogPath, changelog.toString());
 }
 
+/**
+ * Format the given changelog using Prettier. This is extracted into a separate
+ * function for coverage purposes.
+ *
+ * @param changelog - The changelog to format.
+ * @returns The formatted changelog.
+ */
+export function formatChangelog(changelog: string) {
+  return prettier.format(changelog, { parser: 'markdown' });
+}
+
 /**
  * Updates the changelog file of the given package using
  * `@metamask/auto-changelog`. Assumes that the changelog file is located at the
@@ -323,6 +336,7 @@ export async function updatePackageChangelog({
     projectRootDirectory: pkg.directoryPath,
     repoUrl: repositoryUrl,
     tagPrefixes: [`${pkg.validatedManifest.name}@`, 'v'],
+    formatter: formatChangelog,
   });
 
   if (newChangelogContent) {

src/project.test.ts

@@ -3,12 +3,12 @@ import path from 'path';
 import { when } from 'jest-when';
 import { SemVer } from 'semver';
 import * as actionUtils from '@metamask/action-utils';
-import { withSandbox } from '../tests/helpers';
+import { withSandbox } from '../tests/helpers.js';
 import {
   buildMockPackage,
   buildMockProject,
   createNoopWriteStream,
-} from '../tests/unit/helpers';
+} from '../tests/unit/helpers.js';
 import {
   readProject,
   restoreChangelogsForSkippedPackages,

tests/helpers.ts

@@ -126,6 +126,7 @@ export function normalizeMultilineString(string: string): string {
 export function buildChangelog(variantContent: string): string {
   const invariantContent = normalizeMultilineString(`
     # Changelog
+
     All notable changes to this project will be documented in this file.
 
     The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),