From 640c4a376c7beddfa639226607c5f01b54687aec Mon Sep 17 00:00:00 2001
From: Jen Chan <6406037+usrrname@users.noreply.github.com>
Date: Fri, 28 Apr 2023 11:00:10 -0400
Subject: [PATCH] fix(babelParse.ts): in mergedParserOptions, return empty
 array as Symbol.iterator() value if parserOptions.plugins is undefined

---
 code/lib/csf-tools/src/babelParse.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/code/lib/csf-tools/src/babelParse.ts b/code/lib/csf-tools/src/babelParse.ts
index 636bb3af07bd..97c292ab21ca 100644
--- a/code/lib/csf-tools/src/babelParse.ts
+++ b/code/lib/csf-tools/src/babelParse.ts
@@ -13,7 +13,7 @@ function parseWithFlowOrTypescript(source: string, parserOptions: babelParser.Pa
   // Merge the provided parserOptions with the custom parser plugins
   const mergedParserOptions = {
     ...parserOptions,
-    plugins: [...parserOptions.plugins, ...parserPlugins],
+    plugins: [...(parserOptions.plugins ?? []), ...parserPlugins],
   };
 
   return babelParser.parse(source, mergedParserOptions);