From 52a647fa97c351b5127af8001677b2fd70a36341 Mon Sep 17 00:00:00 2001
From: patak-dev <matias.capeletto@gmail.com>
Date: Thu, 28 Apr 2022 21:55:45 +0200
Subject: [PATCH 1/2] fix: inject esbuild helpers in IIFE and UMD wrappers (fix
 #7188, fix #5426)

---
 packages/playground/lib/__tests__/lib.spec.ts | 12 +++++++++
 packages/playground/lib/src/main.js           |  3 +++
 packages/vite/src/node/plugins/esbuild.ts     | 25 +++++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/packages/playground/lib/__tests__/lib.spec.ts b/packages/playground/lib/__tests__/lib.spec.ts
index 382fb16510ce6f..f1e93e90d8357b 100644
--- a/packages/playground/lib/__tests__/lib.spec.ts
+++ b/packages/playground/lib/__tests__/lib.spec.ts
@@ -9,10 +9,22 @@ if (isBuild) {
 
   test('umd', async () => {
     expect(await page.textContent('.umd')).toBe('It works')
+    const code = fs.readFileSync(
+      path.join(testDir, 'dist/my-lib-custom-filename.umd.js'),
+      'utf-8'
+    )
+    // esbuild helpers are injected inside of the UMD wrapper
+    expect(code).toMatch(/^\(function\(/)
   })
 
   test('iife', async () => {
     expect(await page.textContent('.iife')).toBe('It works')
+    const code = fs.readFileSync(
+      path.join(testDir, 'dist/my-lib-custom-filename.iife.js'),
+      'utf-8'
+    )
+    // esbuild helpers are injected inside of the IIFE wrapper
+    expect(code).toMatch(/^var MyLib=function\(\){"use strict";/)
   })
 
   test('Library mode does not include `preload`', async () => {
diff --git a/packages/playground/lib/src/main.js b/packages/playground/lib/src/main.js
index 2422edf5829a0e..3a42dc4718db30 100644
--- a/packages/playground/lib/src/main.js
+++ b/packages/playground/lib/src/main.js
@@ -1,3 +1,6 @@
 export default function myLib(sel) {
+  // Force esbuild helpers
+  console.log({ ...'foo' })
+
   document.querySelector(sel).textContent = 'It works'
 }
diff --git a/packages/vite/src/node/plugins/esbuild.ts b/packages/vite/src/node/plugins/esbuild.ts
index 9e8bae24424d76..bc4a1f780a54d5 100644
--- a/packages/vite/src/node/plugins/esbuild.ts
+++ b/packages/vite/src/node/plugins/esbuild.ts
@@ -26,6 +26,11 @@ import { searchForWorkspaceRoot } from '..'
 
 const debug = createDebugger('vite:esbuild')
 
+const INJECT_HELPERS_IIFE_RE =
+  /(.*)(var [^\s]+=function\(.*\){"use strict";)(.*)/
+const INJECT_HELPERS_UMD_RE =
+  /(.*)(\(function\(.*\){.+amd.+function\(.*\){"use strict";)(.*)/
+
 let server: ViteDevServer
 
 export interface ESBuildOptions extends TransformOptions {
@@ -254,6 +259,26 @@ export const buildEsbuildPlugin = (config: ResolvedConfig): Plugin => {
             }
           : undefined)
       })
+
+      if (config.build.lib) {
+        // #7188, esbuild adds helpers out of the UMD and IIFE wrappers, and the
+        // names are minified potentially causing collision with other globals.
+        // We use a regex to inject the helpers inside the wrappers.
+        // We don't need to create a MagicString here because both the helpers and
+        // the headers don't modify the sourcemap
+        const injectHelpers =
+          opts.format === 'umd'
+            ? INJECT_HELPERS_UMD_RE
+            : opts.format === 'iife'
+            ? INJECT_HELPERS_IIFE_RE
+            : undefined
+        if (injectHelpers) {
+          res.code = res.code.replace(
+            injectHelpers,
+            (_, helpers, header, rest) => header + helpers + rest
+          )
+        }
+      }
       return res
     }
   }

From a36be20db0179594a2fdd8caf313ded6e95a67ad Mon Sep 17 00:00:00 2001
From: patak <matias.capeletto@gmail.com>
Date: Fri, 29 Apr 2022 15:05:27 +0200
Subject: [PATCH 2/2] chore: link to esbuild issue

---
 packages/playground/lib/src/main.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/playground/lib/src/main.js b/packages/playground/lib/src/main.js
index 3a42dc4718db30..cb2fb3b842dc4f 100644
--- a/packages/playground/lib/src/main.js
+++ b/packages/playground/lib/src/main.js
@@ -1,5 +1,5 @@
 export default function myLib(sel) {
-  // Force esbuild helpers
+  // Force esbuild spread helpers (https://github.com/evanw/esbuild/issues/951)
   console.log({ ...'foo' })
 
   document.querySelector(sel).textContent = 'It works'