From 04eafade57b6bd1f9b55e6a2e26d2357aa2aaec7 Mon Sep 17 00:00:00 2001
From: Theodore Brown <theodorejb@outlook.com>
Date: Sat, 25 Feb 2023 23:48:28 -0600
Subject: [PATCH] fix: select first enabled option by default when initial
 value is undefined

Fixes an unintended regression introduced in #6170.

Resolves #7041
---
 src/runtime/internal/dom.ts                                   | 4 +++-
 .../samples/binding-select-initial-value-undefined/_config.js | 4 +++-
 .../binding-select-initial-value-undefined/main.svelte        | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/runtime/internal/dom.ts b/src/runtime/internal/dom.ts
index 52f1198833c6..e73864069c74 100644
--- a/src/runtime/internal/dom.ts
+++ b/src/runtime/internal/dom.ts
@@ -557,7 +557,9 @@ export function select_option(select, value) {
 		}
 	}
 
-	select.selectedIndex = -1; // no option should be selected
+	if (value !== undefined) {
+		select.selectedIndex = -1; // no option should be selected
+	}
 }
 
 export function select_options(select, value) {
diff --git a/test/runtime/samples/binding-select-initial-value-undefined/_config.js b/test/runtime/samples/binding-select-initial-value-undefined/_config.js
index 27bac7ef77d7..c95cd44046f6 100644
--- a/test/runtime/samples/binding-select-initial-value-undefined/_config.js
+++ b/test/runtime/samples/binding-select-initial-value-undefined/_config.js
@@ -5,6 +5,7 @@ export default {
 		<p>selected: a</p>
 
 		<select>
+			<option disabled='' value='x'>x</option>
 			<option value='a'>a</option>
 			<option value='b'>b</option>
 			<option value='c'>c</option>
@@ -18,7 +19,8 @@ export default {
 		const select = target.querySelector('select');
 		const options = [...target.querySelectorAll('option')];
 
+		// first enabled option should be selected
 		assert.equal(select.value, 'a');
-		assert.ok(options[0].selected);
+		assert.ok(options[1].selected);
 	}
 };
diff --git a/test/runtime/samples/binding-select-initial-value-undefined/main.svelte b/test/runtime/samples/binding-select-initial-value-undefined/main.svelte
index 5cb1e9fae794..8c3bd0258f11 100644
--- a/test/runtime/samples/binding-select-initial-value-undefined/main.svelte
+++ b/test/runtime/samples/binding-select-initial-value-undefined/main.svelte
@@ -5,6 +5,7 @@
 <p>selected: {selected}</p>
 
 <select bind:value={selected}>
+	<option disabled>x</option>
 	<option>a</option>
 	<option>b</option>
 	<option>c</option>