From 229422d0502683e80339f46deb9ea3f3a73a8216 Mon Sep 17 00:00:00 2001
From: David Hunt <git@dnotes.net>
Date: Fri, 20 Jan 2023 07:47:57 -0800
Subject: [PATCH] fixes sveltejs/svelte#8214 bind:group to undefined

---
 src/compiler/compile/render_dom/wrappers/Element/Binding.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/compile/render_dom/wrappers/Element/Binding.ts b/src/compiler/compile/render_dom/wrappers/Element/Binding.ts
index 9e2ec85f0f..2e3a5766a3 100644
--- a/src/compiler/compile/render_dom/wrappers/Element/Binding.ts
+++ b/src/compiler/compile/render_dom/wrappers/Element/Binding.ts
@@ -264,7 +264,7 @@ function get_dom_updater(
 		const type = node.get_static_attribute_value('type');
 
 		const condition = type === 'checkbox'
-			? x`~${binding.snippet}.indexOf(${element.var}.__value)`
+			? x`~(${binding.snippet} ?? [])?.indexOf(${element.var}.__value)`
 			: x`${element.var}.__value === ${binding.snippet}`;
 
 		return b`${element.var}.checked = ${condition};`;