diff --git a/packages/vite/src/node/plugins/esbuild.ts b/packages/vite/src/node/plugins/esbuild.ts
index 22fabf27099c00..11f5ea4dd6cec0 100644
--- a/packages/vite/src/node/plugins/esbuild.ts
+++ b/packages/vite/src/node/plugins/esbuild.ts
@@ -27,9 +27,9 @@ import { searchForWorkspaceRoot } from '..'
 const debug = createDebugger('vite:esbuild')
 
 const INJECT_HELPERS_IIFE_RE =
-  /(.*)((?:const|var) [^\s]+=function\([^)]*?\){"use strict";)(.*)/
+  /(.*)((?:const|var) [^\s]+=function\([^)]*?\){"use strict";)(.*)/s
 const INJECT_HELPERS_UMD_RE =
-  /(.*)(\(function\([^)]*?\){.+amd.+function\([^)]*?\){"use strict";)(.*)/
+  /(.*)(\(function\([^)]*?\){.+amd.+function\([^)]*?\){"use strict";)(.*)/s
 
 let server: ViteDevServer
 
diff --git a/playground/lib/vite.config.js b/playground/lib/vite.config.js
index 72c040d38d6dcf..f4cacb9d73d3cc 100644
--- a/playground/lib/vite.config.js
+++ b/playground/lib/vite.config.js
@@ -6,6 +6,11 @@ const path = require('path')
  */
 module.exports = {
   build: {
+    rollupOptions: {
+      output: {
+        banner: `/*!\nMayLib\n*/`
+      }
+    },
     lib: {
       entry: path.resolve(__dirname, 'src/main.js'),
       name: 'MyLib',