From 97d45f85c6cbaa15bbac1c45b08cf302bb115482 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 31 Mar 2026 18:47:54 +0200
Subject: [PATCH] fix: don't override `$destroy/set/on` instance methods in dev
 mode (#18034)

Don't think we need a test for this

Fixes #17988
---
 .changeset/orange-geckos-rest.md                             | 5 +++++
 .../compiler/phases/3-transform/client/transform-client.js   | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/orange-geckos-rest.md

diff --git a/.changeset/orange-geckos-rest.md b/.changeset/orange-geckos-rest.md
new file mode 100644
index 0000000000..5717c249b6
--- /dev/null
+++ b/.changeset/orange-geckos-rest.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: don't override `$destroy/set/on` instance methods in dev mode
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
index 9328d20be3..5cd837d08e 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
@@ -352,7 +352,7 @@ export function client_component(analysis, options) {
 			)
 		);
 	} else if (dev) {
-		component_returned_object.push(b.spread(b.call(b.id('$.legacy_api'))));
+		component_returned_object.unshift(b.spread(b.call(b.id('$.legacy_api'))));
 	}
 
 	const push_args = [b.id('$$props'), b.literal(analysis.runes)];