fix: ignore typescript abstract methods during code transformation

.changeset/tasty-pumas-train.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ignore typescript abstract methods during code transformation

packages/svelte/src/compiler/phases/3-transform/client/visitors/ClassBody.js

@@ -1,6 +1,7 @@
-/** @import { ClassBody, Expression, Identifier, Literal, MethodDefinition, PrivateIdentifier, PropertyDefinition } from 'estree' */
+/** @import { ClassBody, Expression, Identifier, Literal, MethodDefinition, PrivateIdentifier, PropertyDefinition, StaticBlock } from 'estree' */
 /** @import {  } from '#compiler' */
 /** @import { Context, StateField } from '../types' */
+import { deferred } from '../../../../../internal/shared/utils.js';
 import { dev, is_ignored } from '../../../../state.js';
 import * as b from '../../../../utils/builders.js';
 import { regex_invalid_identifier_chars } from '../../../patterns.js';
@@ -13,8 +14,21 @@ import { build_proxy_reassignment, should_proxy } from '../utils.js';
  */
 export function ClassBody(node, context) {
 	if (!context.state.analysis.runes) {
-		context.next();
-		return;
+		/** @type {Array<MethodDefinition | PropertyDefinition | StaticBlock>} */
+		const body = [];
+
+		for (const definition of node.body) {
+			if (
+				definition.type == 'MethodDefinition' &&
+				'abstract' in definition &&
+				definition.abstract
+			) {
+				continue;
+			}
+			body.push(definition);
+		}
+
+		return { ...node, body };
 	}
 
 	/** @type {Map<string, StateField>} */
@@ -30,6 +44,10 @@ export function ClassBody(node, context) {
 	const private_ids = [];
 
 	for (const definition of node.body) {
+		if (definition.type == 'MethodDefinition' && 'abstract' in definition && definition.abstract) {
+			continue;
+		}
+
 		if (
 			(definition.type === 'PropertyDefinition' || definition.type === 'MethodDefinition') &&
 			(definition.key.type === 'Identifier' ||
@@ -95,7 +113,11 @@ export function ClassBody(node, context) {
 	const child_state = { ...context.state, public_state, private_state };
 
 	// Replace parts of the class body
-	for (const definition of node.body) {
+	for (let definition of node.body) {
+		if (definition.type === 'MethodDefinition' && 'abstract' in definition && definition.abstract) {
+			continue;
+		}
+
 		if (
 			definition.type === 'PropertyDefinition' &&
 			(definition.key.type === 'Identifier' ||