From 12bb3babf5a3ad7aacc3e361b9084e83150c450d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BC=98=E6=A0=91=40=E9=98=BF=E9=87=8C?=
 <dickeylth@users.noreply.github.com>
Date: Thu, 10 Feb 2022 18:34:35 +0800
Subject: [PATCH] fix: loader may be undefined

incase typescript check
---
 packages/vite/src/node/optimizer/scan.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/vite/src/node/optimizer/scan.ts b/packages/vite/src/node/optimizer/scan.ts
index f17231c52823e9..0380dc86a79513 100644
--- a/packages/vite/src/node/optimizer/scan.ts
+++ b/packages/vite/src/node/optimizer/scan.ts
@@ -435,7 +435,7 @@ function esbuildScanPlugin(
         }
         const { loader } = config.optimizeDeps?.esbuildOptions ?? {}
         return {
-          loader: loader[`.${ext}`] || ext as Loader,
+          loader: (loader && loader[`.${ext}`]) || ext as Loader,
           contents
         }
       })