feat: add outExtensions option

closes #114

Author: sxzz

package.json

@@ -74,7 +74,7 @@
     "diff": "^7.0.0",
     "find-up-simple": "^1.0.1",
     "rolldown": "^1.0.0-beta.7",
-    "rolldown-plugin-dts": "^0.7.8",
+    "rolldown-plugin-dts": "^0.7.13",
     "tinyexec": "^1.0.1",
     "tinyglobby": "^0.2.12",
     "unconfig": "^7.3.1"

pnpm-lock.yaml

@@ -1,19 +1,17 @@
-import { getPackageType } from '../utils/package'
 import type { NormalizedFormat } from '../options'
-import type { PackageJson } from 'pkg-types'
+import type { PackageType } from '../utils/package'
 
 export type OutputExtension = 'mjs' | 'cjs' | 'js'
 export function resolveOutputExtension(
-  pkg: PackageJson | undefined,
+  packageType: PackageType,
   format: NormalizedFormat,
   fixedExtension?: boolean,
 ): OutputExtension {
-  const moduleType = getPackageType(pkg)
   switch (format) {
     case 'es':
-      return !fixedExtension && moduleType === 'module' ? 'js' : 'mjs'
+      return !fixedExtension && packageType === 'module' ? 'js' : 'mjs'
     case 'cjs':
-      return fixedExtension || moduleType === 'module' ? 'cjs' : 'js'
+      return fixedExtension || packageType === 'module' ? 'cjs' : 'js'
     default:
       return 'js'
   }

src/features/output.ts

@@ -5,6 +5,7 @@ import {
   build as rolldownBuild,
   type BuildOptions,
   type OutputOptions,
+  type PreRenderedChunk,
   type RolldownPluginOption,
 } from 'rolldown'
 import { transformPlugin } from 'rolldown/experimental'
@@ -25,7 +26,7 @@ import {
   type UserConfig,
 } from './options'
 import { debug, logger, setSilent } from './utils/logger'
-import { readPackageJson } from './utils/package'
+import { getPackageType, readPackageJson } from './utils/package'
 import type { PackageJson } from 'pkg-types'
 import type { Options as DtsOptions } from 'rolldown-plugin-dts'
 
@@ -170,10 +171,9 @@ async function getBuildOptions(
     shims,
     fixedExtension,
     tsconfig,
+    outExtensions,
   } = config
 
-  const extension = resolveOutputExtension(pkg, format, fixedExtension)
-
   const plugins: RolldownPluginOption = []
   if (pkg || config.skipNodeModulesBundle) {
     plugins.push(ExternalPlugin(config, pkg))
@@ -223,15 +223,33 @@ async function getBuildOptions(
     [format],
   )
 
+  const packageType = getPackageType(pkg)
+  let jsExtension: string | undefined
+  let dtsExtension: string | undefined
+  if (outExtensions) {
+    const { js, dts } = outExtensions({
+      options: inputOptions,
+      format,
+      pkgType: packageType,
+    })
+    jsExtension = js
+    dtsExtension = dts
+  }
+  jsExtension ||= `.${resolveOutputExtension(packageType, format, fixedExtension)}`
+
   const outputOptions: OutputOptions = await mergeUserOptions(
     {
       format: cjsDts ? 'es' : format,
       name: config.globalName,
       sourcemap,
       dir: outDir,
       minify,
-      entryFileNames: `[name].${extension}`,
-      chunkFileNames: `[name]-[hash].${extension}`,
+      entryFileNames: createChunkFilename('[name]', jsExtension, dtsExtension),
+      chunkFileNames: createChunkFilename(
+        `[name]-[hash]`,
+        jsExtension,
+        dtsExtension,
+      ),
     },
     config.outputOptions,
     [format],
@@ -243,6 +261,17 @@ async function getBuildOptions(
   }
 }
 
+function createChunkFilename(
+  basename: string,
+  jsExtension: string,
+  dtsExtension?: string,
+): string | ((chunk: PreRenderedChunk) => string) {
+  if (!dtsExtension) return `${basename}${jsExtension}`
+  return (chunk: PreRenderedChunk) => {
+    return `${basename}${chunk.name.endsWith('.d') ? dtsExtension : jsExtension}`
+  }
+}
+
 export { defineConfig } from './config'
 export { logger }
 export type { Options, UserConfig }