feat: support ES2026 (Explicit Resource Management)

.changeset/stupid-dancers-lay.md

@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+feat: support ES2026 (Explicit Resource Management)

packages/svelte/package.json

@@ -170,7 +170,7 @@
     "@jridgewell/sourcemap-codec": "^1.5.0",
     "@sveltejs/acorn-typescript": "^1.0.5",
     "@types/estree": "^1.0.5",
-    "acorn": "^8.12.1",
+    "acorn": "^8.15.0",
     "aria-query": "^5.3.1",
     "axobject-query": "^4.1.0",
     "clsx": "^2.1.1",

packages/svelte/src/compiler/phases/1-parse/acorn.js

@@ -50,7 +50,7 @@ export function parse(source, comments, typescript, is_script) {
 		ast = parser.parse(source, {
 			onComment,
 			sourceType: 'module',
-			ecmaVersion: 16,
+			ecmaVersion: 17,
 			locations: true
 		});
 	} finally {
@@ -84,7 +84,7 @@ export function parse_expression_at(source, comments, typescript, index) {
 	const ast = parser.parseExpressionAt(source, index, {
 		onComment,
 		sourceType: 'module',
-		ecmaVersion: 16,
+		ecmaVersion: 17,
 		locations: true
 	});
 

packages/svelte/src/compiler/types/index.d.ts

@@ -283,6 +283,8 @@ export type DeclarationKind =
 	| 'var'
 	| 'let'
 	| 'const'
+	| 'using'
+	| 'await using'
 	| 'function'
 	| 'import'
 	| 'param'

packages/svelte/src/compiler/utils/builders.js

@@ -619,7 +619,8 @@ export function import_all(as, source) {
 	return {
 		type: 'ImportDeclaration',
 		source: literal(source),
-		specifiers: [import_namespace(as)]
+		specifiers: [import_namespace(as)],
+		attributes: []
 	};
 }
 
@@ -636,7 +637,8 @@ export function imports(parts, source) {
 			type: 'ImportSpecifier',
 			imported: id(p[0]),
 			local: id(p[1])
-		}))
+		})),
+		attributes: []
 	};
 }
 

packages/svelte/tests/parser-legacy/samples/each-block-destructured/output.json

@@ -259,7 +259,8 @@
 						"kind": "let"
 					},
 					"specifiers": [],
-					"source": null
+					"source": null,
+					"attributes": []
 				}
 			],
 			"sourceType": "module"

packages/svelte/tests/parser-legacy/samples/script-context-module-unquoted/output.json

@@ -169,7 +169,8 @@
 						"kind": "const"
 					},
 					"specifiers": [],
-					"source": null
+					"source": null,
+					"attributes": []
 				}
 			],
 			"sourceType": "module"

packages/svelte/tests/runtime-legacy/shared.ts

@@ -13,6 +13,8 @@ import type { CompileOptions } from '#compiler';
 import { suite_with_variants, type BaseTest } from '../suite.js';
 import { clear } from '../../src/internal/client/reactivity/batch.js';
 
+const NODE_MAJOR_VERSION = parseInt(process.version.split('.')[0].slice(1));
+
 type Assert = typeof import('vitest').assert & {
 	htmlEqual(a: string, b: string, description?: string): void;
 	htmlEqualWithOptions(
@@ -95,6 +97,7 @@ export interface RuntimeTest<Props extends Record<string, any> = Record<string,
 	expect_unhandled_rejections?: boolean;
 	withoutNormalizeHtml?: boolean | 'only-strip-comments';
 	recover?: boolean;
+	requiredMinimumNodeVersion?: 18 | 20 | 22 | 24;
 }
 
 let unhandled_rejection: Error | null = null;
@@ -127,6 +130,11 @@ export function runtime_suite(runes: boolean) {
 	return suite_with_variants<RuntimeTest, 'hydrate' | 'ssr' | 'dom', CompileOptions>(
 		['dom', 'hydrate', 'ssr'],
 		(variant, config, test_name) => {
+			const { requiredMinimumNodeVersion } = config;
+			if (requiredMinimumNodeVersion && NODE_MAJOR_VERSION < requiredMinimumNodeVersion) {
+				return 'no-test';
+			}
+
 			if (!async_mode && (config.skip_no_async || test_name.startsWith('async-'))) {
 				return true;
 			}

packages/svelte/tests/runtime-runes/samples/using/_config.js

@@ -0,0 +1,11 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: '',
+	requiredMinimumNodeVersion: 24,
+	test({ assert, target }) {
+		flushSync();
+		assert.htmlEqual(target.innerHTML, `<p>connected: true</p><p>disposed: true</p>`);
+	}
+});

packages/svelte/tests/runtime-runes/samples/using/main.svelte

@@ -0,0 +1,18 @@
+<script>
+	let connected = $state(false);
+	let disposed = $state(false);
+
+	const getConn = () => {
+		connected = true;
+		return {
+			[Symbol.dispose]() {
+				disposed = true;
+			}
+		}
+	}
+
+	using conn = getConn();
+</script>
+
+<p>connected: {connected}</p>
+<p>disposed: {disposed}</p>