From fbec895913ee413a80a4ae1ced7c80387d23eb64 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 18 Aug 2025 10:32:39 -0400
Subject: [PATCH] use helper for async bodies

---
 .../3-transform/client/transform-client.js    | 72 ++++++-------------
 .../svelte/src/internal/client/async_body.js  | 14 ++++
 packages/svelte/src/internal/client/index.js  |  1 +
 3 files changed, 36 insertions(+), 51 deletions(-)
 create mode 100644 packages/svelte/src/internal/client/async_body.js

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 eb32f9c98b..1bfd563635 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
@@ -359,22 +359,38 @@ export function client_component(analysis, options) {
 	if (dev) push_args.push(b.id(analysis.name));
 
 	let component_block = b.block([
+		store_init,
 		...store_setup,
 		...legacy_reactive_declarations,
 		...group_binding_declarations,
-		...state.instance_level_snippets,
-		.../** @type {ESTree.Statement[]} */ (instance.body),
-		analysis.runes || !analysis.needs_context
-			? b.empty
-			: b.stmt(b.call('$.init', analysis.immutable ? b.true : undefined))
+		...state.instance_level_snippets
 	]);
 
+	if (analysis.instance.has_await) {
+		const body = b.block([
+			.../** @type {ESTree.Statement[]} */ (instance.body),
+			b.if(b.call('$.aborted'), b.return()),
+			.../** @type {ESTree.Statement[]} */ (template.body)
+		]);
+
+		component_block.body.push(b.stmt(b.call(`$.async_body`, b.arrow([], body, true))));
+	} else {
+		component_block.body.push(
+			.../** @type {ESTree.Statement[]} */ (instance.body),
+			.../** @type {ESTree.Statement[]} */ (template.body)
+		);
+	}
+
 	if (analysis.needs_mutation_validation) {
 		component_block.body.unshift(
 			b.var('$$ownership_validator', b.call('$.create_ownership_validator', b.id('$$props')))
 		);
 	}
 
+	if (!analysis.runes && analysis.needs_context) {
+		component_block.body.push(b.stmt(b.call('$.init', analysis.immutable ? b.true : undefined)));
+	}
+
 	const should_inject_context =
 		dev ||
 		analysis.needs_context ||
@@ -389,52 +405,6 @@ export function client_component(analysis, options) {
 		analysis.uses_slots ||
 		analysis.slot_names.size > 0;
 
-	if (analysis.instance.has_await) {
-		const params = [b.id('$$anchor')];
-		if (should_inject_props) {
-			params.push(b.id('$$props'));
-		}
-		if (store_setup.length > 0) {
-			params.push(b.id('$$stores'));
-		}
-		const body = b.function_declaration(
-			b.id('$$body'),
-			params,
-			b.block([
-				b.var('$$unsuspend', b.call('$.suspend')),
-				b.var('$$active', b.id('$.active_effect')),
-				b.try_catch(
-					b.block([
-						...component_block.body,
-						b.if(b.call('$.aborted'), b.return()),
-						.../** @type {ESTree.Statement[]} */ (template.body)
-					]),
-					b.block([
-						b.if(
-							b.unary('!', b.call('$.aborted', b.id('$$active'))),
-							b.stmt(b.call('$.invoke_error_boundary', b.id('$$error'), b.id('$$active')))
-						)
-					])
-				),
-				b.stmt(b.call('$$unsuspend'))
-			]),
-			true
-		);
-
-		state.hoisted.push(body);
-
-		component_block = b.block([
-			b.var('fragment', b.call('$.comment')),
-			b.var('node', b.call('$.first_child', b.id('fragment'))),
-			store_init,
-			b.stmt(b.call(body.id, b.id('node'), ...params.slice(1))),
-			b.stmt(b.call('$.append', b.id('$$anchor'), b.id('fragment')))
-		]);
-	} else {
-		component_block.body.unshift(store_init);
-		component_block.body.push(.../** @type {ESTree.Statement[]} */ (template.body));
-	}
-
 	// trick esrap into including comments
 	component_block.loc = instance.loc;
 
diff --git a/packages/svelte/src/internal/client/async_body.js b/packages/svelte/src/internal/client/async_body.js
new file mode 100644
index 0000000000..2336e25ae2
--- /dev/null
+++ b/packages/svelte/src/internal/client/async_body.js
@@ -0,0 +1,14 @@
+import { suspend } from './reactivity/batch.js';
+
+/**
+ * @param {() => Promise<void>} fn
+ */
+export async function async_body(fn) {
+	const unsuspend = suspend();
+
+	try {
+		await fn();
+	} finally {
+		unsuspend();
+	}
+}
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index 4089401a7e..3e030cbd2d 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -1,5 +1,6 @@
 export { createAttachmentKey as attachment } from '../../attachments/index.js';
 export { FILENAME, HMR, NAMESPACE_SVG } from '../../constants.js';
+export { async_body } from './async_body.js';
 export { push, pop, add_svelte_meta } from './context.js';
 export { assign, assign_and, assign_or, assign_nullish } from './dev/assign.js';
 export { cleanup_styles } from './dev/css.js';