From 36315fece462cf1a2afc4f1d44f9f527df3ae7db Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Sat, 14 Jun 2025 04:18:52 -0700
Subject: [PATCH] fix: prune typescript class field declarations (#16154)

* fix: prune typescript class field declarations

* add test
---
 .changeset/neat-lemons-occur.md                     |  5 +++++
 .../phases/1-parse/remove_typescript_nodes.js       | 13 +++++++++++++
 .../runtime-runes/samples/typescript/main.svelte    |  1 +
 3 files changed, 19 insertions(+)
 create mode 100644 .changeset/neat-lemons-occur.md

diff --git a/.changeset/neat-lemons-occur.md b/.changeset/neat-lemons-occur.md
new file mode 100644
index 0000000000..53d77ed764
--- /dev/null
+++ b/.changeset/neat-lemons-occur.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prune typescript class field declarations
diff --git a/packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js b/packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js
index aba94ee20d..cb498c3c13 100644
--- a/packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js
+++ b/packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js
@@ -115,6 +115,19 @@ const visitors = {
 	TSDeclareFunction() {
 		return b.empty;
 	},
+	ClassBody(node, context) {
+		const body = [];
+		for (const _child of node.body) {
+			const child = context.visit(_child);
+			if (child.type !== 'PropertyDefinition' || !child.declare) {
+				body.push(child);
+			}
+		}
+		return {
+			...node,
+			body
+		};
+	},
 	ClassDeclaration(node, context) {
 		if (node.declare) {
 			return b.empty;
diff --git a/packages/svelte/tests/runtime-runes/samples/typescript/main.svelte b/packages/svelte/tests/runtime-runes/samples/typescript/main.svelte
index d1b6452df4..4fc7c4ec38 100644
--- a/packages/svelte/tests/runtime-runes/samples/typescript/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/typescript/main.svelte
@@ -14,6 +14,7 @@
 
 	class Foo<T> {
 		public name: string;
+		declare bar: string;
 		x = 'x' as const;
 		constructor(name: string) {
 			this.name = name;