From dba3cf8e0f96d6ed191e3d816c3db882070c3418 Mon Sep 17 00:00:00 2001
From: sapphi-red <49056869+sapphi-red@users.noreply.github.com>
Date: Fri, 5 May 2023 17:38:50 +0900
Subject: [PATCH] fix: preserve top-level when running terser for IIFE

---
 src/index.ts          |  1 +
 src/plugins/terser.ts |  6 ++++--
 test/index.test.ts    | 17 ++++++++++++++++-
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 64e062d2..ffb09f70 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -265,6 +265,7 @@ export async function build(_options: Options) {
                       minifyOptions: options.minify,
                       format,
                       terserOptions: options.terserOptions,
+                      globalName: options.globalName,
                     }),
                   ])
                   await runEsbuild(options, {
diff --git a/src/plugins/terser.ts b/src/plugins/terser.ts
index 78168ace..04172546 100644
--- a/src/plugins/terser.ts
+++ b/src/plugins/terser.ts
@@ -11,10 +11,12 @@ export const terserPlugin = ({
   minifyOptions,
   format,
   terserOptions = {},
+  globalName
 }: {
   minifyOptions: Options['minify']
   format: Format
-  terserOptions?: MinifyOptions
+  terserOptions?: MinifyOptions,
+  globalName?: string
 }): Plugin => {
   return {
     name: 'terser',
@@ -37,7 +39,7 @@ export const terserPlugin = ({
 
       if (format === 'esm') {
         defaultOptions.module = true
-      } else {
+      } else if (!(format === 'iife' && globalName !== undefined)) {
         defaultOptions.toplevel = true
       }
 
diff --git a/test/index.test.ts b/test/index.test.ts
index 9e7c71e8..8c83be38 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -1266,4 +1266,19 @@ test('custom inject style function', async () => {
   expect(outFiles).toEqual(['input.js', 'input.mjs'])
   expect(await getFileContent('dist/input.mjs')).toContain('__custom_inject_style__(`.hello{color:red}\n`)')
   expect(await getFileContent('dist/input.js')).toContain('__custom_inject_style__(`.hello{color:red}\n`)')
-})
\ No newline at end of file
+})
+
+test('preserve top-level variable for IIFE format', async () => {
+  const { outFiles, getFileContent } = await run(getTestName(), {
+    'input.ts': `export default 'foo'`,
+    'tsup.config.ts': `
+        export default {
+          entry: ['src/input.ts'],
+          globalName: 'globalFoo',
+          minify: 'terser',
+          format: ['iife']
+        }`,
+  })
+  expect(outFiles).toEqual(['input.global.js'])
+  expect(await getFileContent('dist/input.global.js')).toMatch(/globalFoo\s*=/)
+})