docs/README.md

@@ -145,16 +145,12 @@ Provide the following configuration in your `.vscode/settings.json` (or global)
   "json.schemas": [
     {
       "url": "https://cdn.jsdelivr.net/npm/tsup/schema.json",
-      "fileMatch": [
-        "package.json",
-        "tsup.config.json"
-      ]
+      "fileMatch": ["package.json", "tsup.config.json"]
     }
   ]
 }
 ```
 
-
 ### Multiple entrypoints
 
 Beside using positional arguments `tsup [...files]` to specify multiple entrypoints, you can also use the cli flag `--entry`:
@@ -164,7 +160,7 @@ Beside using positional arguments `tsup [...files]` to specify multiple entrypoi
 tsup --entry src/a.ts --entry src/b.ts
 ```
 
-The associated output file names can be defined as follows: 
+The associated output file names can be defined as follows:
 
 ```bash
 # Outputs `dist/foo.js` and `dist/bar.js`.
@@ -350,6 +346,14 @@ tsup src/index.ts --env.NODE_ENV production
 
 When an entry file like `src/cli.ts` contains hashbang like `#!/bin/env node` tsup will automatically make the output file executable, so you don't have to run `chmod +x dist/cli.js`.
 
+### Interop with CommonJS
+
+By default, esbuild will transform `export default x` to `module.exports.default = x` in CommonJS, but you can change this behavior by using the `--cjsInterop` flag: If there are only default exports and no named exports, it will be transformed to `module.exports = x` instead.
+
+```bash
+tsup src/index.ts --cjsInterop
+```
+
 ### Watch mode
 
 ```bash

package.json

@@ -60,15 +60,15 @@
     "prettier": "2.5.1",
     "resolve": "1.20.0",
     "rollup-plugin-dts": "5.3.0",
-    "rollup-plugin-hashbang": "2.2.2",
+    "rollup-plugin-hashbang": "3.0.0",
     "sass": "1.62.1",
     "strip-json-comments": "4.0.0",
     "svelte": "3.46.4",
     "svelte-preprocess": "5.0.3",
     "terser": "^5.16.0",
     "ts-essentials": "9.1.2",
     "tsconfig-paths": "3.12.0",
-    "tsup": "6.6.1",
+    "tsup": "7.1.0",
     "typescript": "5.0.2",
     "vitest": "0.28.4",
     "wait-for-expect": "3.0.2"

src/cli-main.ts

@@ -91,6 +91,11 @@ export async function main(options: Options = {}) {
       'Using Rollup for treeshaking instead, "recommended" or "smallest" or "safest"'
     )
     .option('--publicDir [dir]', 'Copy public directory to output directory')
+    .option(
+      '--killSignal <signal>',
+      'Signal to kill child process, "SIGTERM" or "SIGKILL"'
+    )
+    .option('--cjsInterop', 'Enable cjs interop')
     .action(async (files: string[], flags) => {
       const { build } = await import('.')
       Object.assign(options, {

src/index.ts

@@ -11,7 +11,7 @@ import execa from 'execa'
 import kill from 'tree-kill'
 import { version } from '../package.json'
 import { createLogger, setSilent } from './log'
-import { NormalizedOptions, Format, Options } from './options'
+import { NormalizedOptions, Format, Options, KILL_SIGNAL } from './options'
 import { runEsbuild } from './esbuild'
 import { shebang } from './plugins/shebang'
 import { cjsSplitting } from './plugins/cjs-splitting'
@@ -21,6 +21,7 @@ import { sizeReporter } from './plugins/size-reporter'
 import { treeShakingPlugin } from './plugins/tree-shaking'
 import { copyPublicDir, isInPublicDir } from './lib/public-dir'
 import { terserPlugin } from './plugins/terser'
+import { cjsInterop } from './plugins/cjs-interop'
 
 export type { Format, Options, NormalizedOptions }
 
@@ -34,15 +35,12 @@ export const defineConfig = (
       ) => MaybePromise<Options | Options[]>)
 ) => options
 
-const killProcess = ({
-  pid,
-  signal = 'SIGTERM',
-}: {
-  pid: number
-  signal?: string | number
-}) =>
-  new Promise<unknown>((resolve) => {
-    kill(pid, signal, resolve)
+const killProcess = ({ pid, signal }: { pid: number; signal: KILL_SIGNAL }) =>
+  new Promise<void>((resolve, reject) => {
+    kill(pid, signal, (err) => {
+      if (err) return reject(err)
+      resolve()
+    })
   })
 
 const normalizeOptions = async (
@@ -207,6 +205,7 @@ export async function build(_options: Options) {
               if (onSuccessProcess) {
                 await killProcess({
                   pid: onSuccessProcess.pid,
+                  signal: options.killSignal || 'SIGTERM',
                 })
               } else if (onSuccessCleanup) {
                 await onSuccessCleanup()
@@ -256,6 +255,7 @@ export async function build(_options: Options) {
                       silent: options.silent,
                     }),
                     cjsSplitting(),
+                    cjsInterop(),
                     es5(),
                     sizeReporter(),
                     terserPlugin({

src/options.ts

@@ -5,6 +5,8 @@ import type { Plugin } from './plugin'
 import type { TreeshakingStrategy } from './plugins/tree-shaking'
 import type { MinifyOptions } from 'terser'
 
+export type KILL_SIGNAL = 'SIGKILL' | 'SIGTERM'
+
 export type Format = 'cjs' | 'esm' | 'iife'
 
 export type ContextForOutPathGeneration = {
@@ -14,7 +16,7 @@ export type ContextForOutPathGeneration = {
   pkgType?: string
 }
 
-export type OutExtensionObject = { js?: string, dts?: string }
+export type OutExtensionObject = { js?: string; dts?: string }
 
 export type OutExtensionFactory = (
   ctx: ContextForOutPathGeneration
@@ -221,6 +223,12 @@ export type Options = {
    * Copy the files inside `publicDir` to output directory
    */
   publicDir?: string | boolean
+  killSignal?: KILL_SIGNAL
+  /**
+   * Interop default within `module.exports` in cjs
+   * @default false
+   */
+  cjsInterop?: boolean
 }
 
 export type NormalizedOptions = Omit<

src/plugins/cjs-interop.ts

@@ -0,0 +1,26 @@
+import { Plugin } from '../plugin'
+
+export const cjsInterop = (): Plugin => {
+  return {
+    name: 'cjs-interop',
+
+    async renderChunk(code, info) {
+      if (
+        !this.options.cjsInterop ||
+        this.format !== 'cjs' ||
+        info.type !== 'chunk' ||
+        !/\.(js|cjs)$/.test(info.path) ||
+        !info.entryPoint ||
+        info.exports?.length !== 1 ||
+        info.exports[0] !== 'default'
+      ) {
+        return
+      }
+
+      return {
+        code: code + '\nmodule.exports = exports.default',
+        map: info.map,
+      }
+    },
+  }
+}

src/rollup.ts

@@ -132,12 +132,22 @@ const getRollupConfig = async (
     },
   }
 
-  const fixEnumDeclaration: Plugin = {
-    name: 'tsup:fix-enum-declaration',
-    renderChunk(code) {
-      // make sure enum declaration starts with `declare`
-      // #834
-      return code.replace(/^(\s*)enum\s/gm, '$1declare enum ')
+  const fixCjsExport: Plugin = {
+    name: 'tsup:fix-cjs-export',
+    renderChunk(code, info) {
+      if (
+        info.type !== 'chunk' ||
+        !/\.(ts|cts)$/.test(info.fileName) ||
+        !info.isEntry ||
+        info.exports?.length !== 1 ||
+        info.exports[0] !== 'default'
+      )
+        return
+
+      return code.replace(
+        /(?<=(?<=[;}]|^)\s*export\s*){\s*([\w$]+)\s*as\s+default\s*}/,
+        `= $1`
+      )
     },
   }
 
@@ -181,15 +191,14 @@ const getRollupConfig = async (
             target: ts.ScriptTarget.ESNext,
           },
         }),
-        fixEnumDeclaration,
       ].filter(Boolean),
       external: [
         // Exclude dependencies, e.g. `lodash`, `lodash/get`
         ...deps.map((dep) => new RegExp(`^${dep}($|\\/|\\\\)`)),
         ...(options.external || []),
       ],
     },
-    outputConfig: options.format.map((format) => {
+    outputConfig: options.format.map((format): OutputOptions => {
       const outputExtension =
         options.outExtension?.({ format, options, pkgType: pkg.type }).dts ||
         defaultOutExtension({ format, pkgType: pkg.type }).dts
@@ -200,6 +209,9 @@ const getRollupConfig = async (
         banner: dtsOptions.banner,
         footer: dtsOptions.footer,
         entryFileNames: `[name]${outputExtension}`,
+        plugins: [
+          format === 'cjs' && options.cjsInterop && fixCjsExport,
+        ].filter(Boolean),
       }
     }),
   }

tsup.config.ts

@@ -2,7 +2,7 @@ import { defineConfig } from 'tsup'
 
 export default defineConfig({
   name: 'tsup',
-  target: 'node14',
+  target: 'node16.14',
   dts: {
     resolve: true,
     // build types for `src/index.ts` only