Ability to skip changelog creation when there are no changes.

src/application/Apexdocs.ts

@@ -76,7 +76,6 @@ async function processChangeLog(config: UserDefinedChangelogConfig) {
   return pipe(
     TE.tryCatch(loadFiles, (e) => new FileReadingError('An error occurred while reading files.', e)),
     TE.flatMap(([previous, current]) => changelog(previous, current, config)),
-    TE.map(() => '✔️ Changelog generated successfully!'),
     TE.mapLeft(toErrors),
   );
 }

src/application/generators/changelog.ts

@@ -1,25 +1,32 @@
 import { pipe } from 'fp-ts/function';
-import { PageData, UnparsedSourceFile, UserDefinedChangelogConfig } from '../../core/shared/types';
+import { PageData, Skip, UnparsedSourceFile, UserDefinedChangelogConfig } from '../../core/shared/types';
 import * as TE from 'fp-ts/TaskEither';
 import { writeFiles } from '../file-writer';
 import { ChangeLogPageData, generateChangeLog } from '../../core/changelog/generate-change-log';
 import { FileWritingError } from '../errors';
+import { isSkip } from '../../core/shared/utils';
 
 export default function generate(
   oldBundles: UnparsedSourceFile[],
   newBundles: UnparsedSourceFile[],
   config: UserDefinedChangelogConfig,
 ) {
-  return pipe(
-    generateChangeLog(oldBundles, newBundles, config),
-    TE.flatMap((files) => writeFilesToSystem(files, config.targetDir)),
-  );
+  function handleFile(file: ChangeLogPageData | Skip) {
+    if (isSkip(file)) {
+      return TE.right('✔️ Done! Skipped writing files to the system.');
+    }
+
+    return writeFilesToSystem(file, config.targetDir);
+  }
+
+  return pipe(generateChangeLog(oldBundles, newBundles, config), TE.flatMap(handleFile));
 }
 
 function writeFilesToSystem(pageData: ChangeLogPageData, outputDir: string) {
   return pipe(
     [pageData],
     (files) => writeFiles(files as PageData[], outputDir),
+    TE.map(() => '✔️ Changelog generated successfully!'),
     TE.mapLeft((error) => {
       return new FileWritingError('An error occurred while writing files to the system.', error);
     }),

src/cli/commands/changelog.ts

@@ -35,4 +35,9 @@ export const changeLogOptions: { [key: string]: Options } = {
       'Values should be separated by a space, e.g --scope global public namespaceaccessible. ' +
       'Annotations are supported and should be passed lowercased and without the @ symbol, e.g. namespaceaccessible auraenabled.',
   },
+  skipIfNoChanges: {
+    type: 'boolean',
+    default: changeLogDefaults.skipIfNoChanges,
+    describe: 'Skip the changelog generation if there are no changes between the previous and current version.',
+  },
 };

src/core/changelog/__test__/generating-change-log.spec.ts

@@ -1,6 +1,7 @@
 import { UnparsedSourceFile } from '../../shared/types';
-import { generateChangeLog } from '../generate-change-log';
+import { ChangeLogPageData, generateChangeLog } from '../generate-change-log';
 import { assertEither } from '../../test-helpers/assert-either';
+import { isSkip } from '../../shared/utils';
 
 const config = {
   fileName: 'changelog',
@@ -9,13 +10,26 @@ const config = {
   currentVersionDir: '',
   previousVersionDir: '',
   exclude: [],
+  skipIfNoChanges: false,
 };
 
 describe('when generating a changelog', () => {
+  it('should not skip when skipIfNoChanges, even if there are no changes', async () => {
+    const result = await generateChangeLog([], [], { ...config })();
+
+    assertEither(result, (data) => expect(isSkip(data)).toBe(false));
+  });
+
+  it('should skip when there are no changes', async () => {
+    const result = await generateChangeLog([], [], { ...config, skipIfNoChanges: true })();
+
+    assertEither(result, (data) => expect(isSkip(data)).toBe(true));
+  });
+
   it('should return a file path', async () => {
     const result = await generateChangeLog([], [], config)();
 
-    assertEither(result, (data) => expect(data.outputDocPath).toContain('changelog.md'));
+    assertEither(result, (data) => expect((data as ChangeLogPageData).outputDocPath).toContain('changelog.md'));
   });
 
   describe('that does not include new classes', () => {
@@ -25,7 +39,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).not.toContain('## New Classes'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).not.toContain('## New Classes'));
     });
   });
 
@@ -40,7 +54,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('## New Classes'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('## New Classes'));
     });
 
     it('should include the new class name', async () => {
@@ -53,7 +67,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('### Test'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('### Test'));
     });
 
     it('should include the new class description', async () => {
@@ -71,7 +85,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('This is a test class.'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('This is a test class.'));
     });
   });
 
@@ -86,7 +100,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('## New Interfaces'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('## New Interfaces'));
     });
 
     it('should include the new interface name', async () => {
@@ -99,7 +113,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('### Test'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('### Test'));
     });
 
     it('should include the new interface description', async () => {
@@ -117,7 +131,9 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('This is a test interface.'));
+      assertEither(result, (data) =>
+        expect((data as ChangeLogPageData).content).toContain('This is a test interface.'),
+      );
     });
   });
 
@@ -130,7 +146,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('## New Enums'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('## New Enums'));
     });
 
     it('should include the new enum name', async () => {
@@ -141,7 +157,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('### Test'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('### Test'));
     });
 
     it('should include the new enum description', async () => {
@@ -157,7 +173,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('This is a test enum.'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('This is a test enum.'));
     });
   });
 
@@ -172,7 +188,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, { ...config, scope: ['global'] })();
 
-      assertEither(result, (data) => expect(data.content).not.toContain('## New Classes'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).not.toContain('## New Classes'));
     });
   });
 
@@ -187,7 +203,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('## Removed Types'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('## Removed Types'));
     });
 
     it('should include the removed type name', async () => {
@@ -200,7 +216,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('- Test'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('- Test'));
     });
   });
 
@@ -219,7 +235,9 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('## New or Modified Members in Existing Types'));
+      assertEither(result, (data) =>
+        expect((data as ChangeLogPageData).content).toContain('## New or Modified Members in Existing Types'),
+      );
     });
 
     it('should include the new or modified type name', async () => {
@@ -236,7 +254,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('### Test'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('### Test'));
     });
 
     it('should include the new or modified member name', async () => {
@@ -253,7 +271,7 @@ describe('when generating a changelog', () => {
 
       const result = await generateChangeLog(oldBundle, newBundle, config)();
 
-      assertEither(result, (data) => expect(data.content).toContain('myMethod'));
+      assertEither(result, (data) => expect((data as ChangeLogPageData).content).toContain('myMethod'));
     });
   });
 });

src/core/changelog/generate-change-log.ts

@@ -1,14 +1,15 @@
-import { ParsedFile, UnparsedSourceFile, UserDefinedChangelogConfig } from '../shared/types';
+import { ParsedFile, Skip, UnparsedSourceFile, UserDefinedChangelogConfig } from '../shared/types';
 import { pipe } from 'fp-ts/function';
 import * as TE from 'fp-ts/TaskEither';
 import { reflectBundles } from '../reflection/reflect-source';
-import { processChangelog, VersionManifest } from './process-changelog';
+import { Changelog, hasChanges, processChangelog, VersionManifest } from './process-changelog';
 import { convertToRenderableChangelog, RenderableChangelog } from './renderable-changelog';
 import { CompilationRequest, Template } from '../template';
 import { changelogTemplate } from './templates/changelog-template';
 import { ReflectionErrors } from '../errors/errors';
 import { apply } from '#utils/fp';
 import { filterScope } from '../reflection/filter-scope';
+import { skip } from '../../index';
 
 export type ChangeLogPageData = {
   content: string;
@@ -19,7 +20,7 @@ export function generateChangeLog(
   oldBundles: UnparsedSourceFile[],
   newBundles: UnparsedSourceFile[],
   config: Omit<UserDefinedChangelogConfig, 'targetGenerator'>,
-): TE.TaskEither<ReflectionErrors, ChangeLogPageData> {
+): TE.TaskEither<ReflectionErrors, ChangeLogPageData | Skip> {
   const filterOutOfScope = apply(filterScope, config.scope);
 
   function reflect(sourceFiles: UnparsedSourceFile[]) {
@@ -28,18 +29,23 @@ export function generateChangeLog(
 
   const convertToPageData = apply(toPageData, config.fileName);
 
+  function handleConversion({ changelog, newManifest }: { changelog: Changelog; newManifest: VersionManifest }) {
+    if (config.skipIfNoChanges && !hasChanges(changelog)) {
+      return skip();
+    }
+    return pipe(convertToRenderableChangelog(changelog, newManifest.types), compile, convertToPageData);
+  }
+
   return pipe(
     reflect(oldBundles),
     TE.bindTo('oldVersion'),
     TE.bind('newVersion', () => reflect(newBundles)),
     TE.map(toManifests),
     TE.map(({ oldManifest, newManifest }) => ({
-      changeLog: processChangelog(oldManifest, newManifest),
+      changelog: processChangelog(oldManifest, newManifest),
       newManifest,
     })),
-    TE.map(({ changeLog, newManifest }) => convertToRenderableChangelog(changeLog, newManifest.types)),
-    TE.map(compile),
-    TE.map(convertToPageData),
+    TE.map(handleConversion),
   );
 }
 

src/core/changelog/process-changelog.ts

@@ -34,6 +34,12 @@ export type Changelog = {
   newOrModifiedMembers: NewOrModifiedMember[];
 };
 
+export function hasChanges(changelog: Changelog): boolean {
+  return (
+    changelog.newTypes.length > 0 || changelog.removedTypes.length > 0 || changelog.newOrModifiedMembers.length > 0
+  );
+}
+
 export function processChangelog(oldVersion: VersionManifest, newVersion: VersionManifest): Changelog {
   return {
     newTypes: getNewTypes(oldVersion, newVersion),

src/core/shared/types.d.ts

@@ -48,6 +48,7 @@ export type UserDefinedChangelogConfig = {
   fileName: string;
   scope: string[];
   exclude: string[];
+  skipIfNoChanges: boolean;
 };
 
 export type UserDefinedConfig = UserDefinedMarkdownConfig | UserDefinedOpenApiConfig | UserDefinedChangelogConfig;

src/defaults.ts

@@ -27,4 +27,5 @@ export const changeLogDefaults = {
   fileName: 'changelog',
   scope: ['global'],
   exclude: [],
+  skipIfNoChanges: true,
 };