feat: 🎸 dtsOnly mode

Author: Sunny-117

.claude/settings.local.json

@@ -42,7 +42,8 @@
       "Bash(git restore:*)",
       "Bash(pnpm test:coverage:*)",
       "Bash(pnpm docs:build:*)",
-      "Bash(git checkout:*)"
+      "Bash(git checkout:*)",
+      "Bash(pnpm test:types:*)"
     ]
   }
 }

src/builders/bundle.ts

@@ -8,7 +8,7 @@ import type {
 } from 'rolldown'
 import type { Options as DtsOptions } from 'rolldown-plugin-dts'
 import type { BuildConfig, BuildContext, BuildHooks, BundleEntry } from '../types'
-import { mkdir, readFile, writeFile } from 'node:fs/promises'
+import { mkdir, readFile, unlink, writeFile } from 'node:fs/promises'
 import { builtinModules } from 'node:module'
 import { basename, dirname, extname, join, relative, resolve } from 'node:path'
 import { colors as c } from 'consola/utils'
@@ -77,8 +77,9 @@ export async function rolldownBuild(
     logger.info('Running in dtsOnly mode - only generating declaration files')
     // Force dts to be enabled
     entry.dts = entry.dts === false ? true : (entry.dts || true)
-    // We'll skip the normal build and only run DTS generation
-    // This will be handled in the format loop below
+    // Force ESM format since DTS plugin only works with ESM
+    formats.length = 0
+    formats.push('esm')
   }
 
   if (entry.stub) {
@@ -432,6 +433,40 @@ export async function rolldownBuild(
     }
   }
 
+  // Handle dtsOnly mode: delete JS files, keep only .d.ts files
+  if (entry.dtsOnly) {
+    const jsFilesToDelete: string[] = []
+    for (const outputEntry of allOutputEntries) {
+      const filePath = filePathMap.get(outputEntry.name)
+      if (filePath && !filePath.endsWith('.d.ts') && !filePath.endsWith('.d.mts') && !filePath.endsWith('.d.cts')) {
+        jsFilesToDelete.push(filePath)
+      }
+    }
+    // Delete JS files
+    for (const filePath of jsFilesToDelete) {
+      try {
+        await unlink(filePath)
+        // Also try to delete sourcemap if exists
+        try {
+          await unlink(`${filePath}.map`)
+        }
+        catch {
+          // ignore if no map file
+        }
+      }
+      catch {
+        // ignore if file doesn't exist
+      }
+    }
+    // Filter out JS entries from output display
+    const dtsEntries = allOutputEntries.filter(o =>
+      o.name.endsWith('.d.ts') || o.name.endsWith('.d.mts') || o.name.endsWith('.d.cts'),
+    )
+    // Clear and re-add only DTS entries
+    allOutputEntries.length = 0
+    allOutputEntries.push(...dtsEntries)
+  }
+
   // Copy files if specified
   if (entry.copy) {
     await copyFiles(ctx.pkgDir, fullOutDir, entry.copy)

test/__snapshots__/bundle.test.ts.snap

@@ -124,6 +124,34 @@ return exports;
 "
 `;
 
+exports[`bundle mode > dtsOnly mode > should force ESM format in dtsOnly mode even if cjs is specified 1`] = `
+"## index.d.mts
+
+\`\`\`ts
+//#region index.d.ts
+declare const value = 42;
+//#endregion
+export { value };
+\`\`\`
+"
+`;
+
+exports[`bundle mode > dtsOnly mode > should only generate .d.ts files when dtsOnly is true 1`] = `
+"## index.d.mts
+
+\`\`\`ts
+//#region index.d.ts
+interface User {
+  name: string;
+  age: number;
+}
+declare function greet(user: User): string;
+//#endregion
+export { User, greet };
+\`\`\`
+"
+`;
+
 exports[`bundle mode > external dependencies > should handle external dependencies 1`] = `
 "## index.mjs
 

test/bundle.test.ts

@@ -365,4 +365,71 @@ describe('bundle mode', () => {
       })
     })
   })
+
+  describe('dtsOnly mode', () => {
+    it('should only generate .d.ts files when dtsOnly is true', async (context) => {
+      await testBuild({
+        context,
+        files: {
+          'index.ts': `
+            export interface User {
+              name: string
+              age: number
+            }
+            export function greet(user: User): string {
+              return \`Hello, \${user.name}!\`
+            }
+          `,
+        },
+        config: {
+          entries: [
+            {
+              type: 'bundle',
+              input: 'index.ts',
+              dtsOnly: true,
+            },
+          ],
+        },
+        afterBuild: async (outputDir) => {
+          const { readdirSync } = await import('node:fs')
+          const files = readdirSync(outputDir)
+          // Should only have .d.ts files, no .mjs files
+          const jsFiles = files.filter(f => f.endsWith('.mjs') || f.endsWith('.js') || f.endsWith('.cjs'))
+          const dtsFiles = files.filter(f => f.endsWith('.d.ts') || f.endsWith('.d.mts'))
+          expect(jsFiles.length).toBe(0)
+          expect(dtsFiles.length).toBeGreaterThan(0)
+        },
+      })
+    })
+
+    it('should force ESM format in dtsOnly mode even if cjs is specified', async (context) => {
+      await testBuild({
+        context,
+        files: {
+          'index.ts': `
+            export const value = 42
+          `,
+        },
+        config: {
+          entries: [
+            {
+              type: 'bundle',
+              input: 'index.ts',
+              format: 'cjs',
+              dtsOnly: true,
+            },
+          ],
+        },
+        afterBuild: async (outputDir) => {
+          const { readdirSync } = await import('node:fs')
+          const files = readdirSync(outputDir)
+          // Should only have .d.ts files
+          const jsFiles = files.filter(f => f.endsWith('.mjs') || f.endsWith('.js') || f.endsWith('.cjs'))
+          const dtsFiles = files.filter(f => f.endsWith('.d.ts') || f.endsWith('.d.mts'))
+          expect(jsFiles.length).toBe(0)
+          expect(dtsFiles.length).toBeGreaterThan(0)
+        },
+      })
+    })
+  })
 })