From 197e01f95652f511160f38b37b9da73a124ecd48 Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Tue, 19 Dec 2023 11:47:36 -0500
Subject: [PATCH] Revert "fix: build service workers in IIFE format" (#11400)

* Revert "fix: build service workers in IIFE format (#11129)"

This reverts commit 5f052a34572f439894ade2c6ef37bae573a96b16.

* better fix

* changeset

* remove format

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
---
 .changeset/green-cycles-shake.md                         | 5 +++++
 .changeset/tricky-meals-perform.md                       | 5 -----
 .../kit/src/exports/vite/build/build_service_worker.js   | 9 +++++----
 3 files changed, 10 insertions(+), 9 deletions(-)
 create mode 100644 .changeset/green-cycles-shake.md
 delete mode 100644 .changeset/tricky-meals-perform.md

diff --git a/.changeset/green-cycles-shake.md b/.changeset/green-cycles-shake.md
new file mode 100644
index 000000000000..5b0d39476f01
--- /dev/null
+++ b/.changeset/green-cycles-shake.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: prevent esbuild adding phantom exports to service worker
diff --git a/.changeset/tricky-meals-perform.md b/.changeset/tricky-meals-perform.md
deleted file mode 100644
index 029af8321852..000000000000
--- a/.changeset/tricky-meals-perform.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-'@sveltejs/kit': patch
----
-
-fix: build service workers in IIFE format
diff --git a/packages/kit/src/exports/vite/build/build_service_worker.js b/packages/kit/src/exports/vite/build/build_service_worker.js
index 8bb292dc68c6..3d3849c6d727 100644
--- a/packages/kit/src/exports/vite/build/build_service_worker.js
+++ b/packages/kit/src/exports/vite/build/build_service_worker.js
@@ -70,10 +70,8 @@ export async function build_service_worker(
 					'service-worker': service_worker_entry_file
 				},
 				output: {
-					// default 'es' format would be nicer
-					// iife is workaround for https://github.com/vitejs/vite/issues/15379
-					format: 'iife',
-					entryFileNames: '[name].js',
+					// .mjs so that esbuild doesn't incorrectly inject `export` https://github.com/vitejs/vite/issues/15379
+					entryFileNames: 'service-worker.mjs',
 					assetFileNames: `${kit.appDir}/immutable/assets/[name].[hash][extname]`,
 					inlineDynamicImports: true
 				}
@@ -95,4 +93,7 @@ export async function build_service_worker(
 			}
 		}
 	});
+
+	// rename .mjs to .js to avoid incorrect MIME types with ancient webservers
+	fs.renameSync(`${out}/client/service-worker.mjs`, `${out}/client/service-worker.js`);
 }