make it work in dev

packages/svelte/src/compiler/phases/3-transform/client/types.d.ts

@@ -97,6 +97,7 @@ export interface ParallelizedChunk {
 	/** index in instance body */
 	position: number;
 	bindings: Binding[];
+	type: 'promise_all' | 'all';
 }
 
 export type Context = import('zimmerframe').Context<AST.SvelteNode, ClientTransformState>;

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

@@ -152,12 +152,17 @@ export function Program(node, context) {
 					chunk.position + offset,
 					0,
 					b.declaration(chunk.kind, [
-						b.declarator(declarator.id, b.call(b.await(b.call('$.save', declarator.init))))
+						b.declarator(
+							declarator.id,
+							chunk.type === 'promise_all'
+								? b.await(declarator.init)
+								: b.call(b.await(b.call('$.save', declarator.init)))
+						)
 					])
 				);
 			} else {
 				const pattern = b.array_pattern(chunk.declarators.map(({ id }) => id));
-				const init = b.call('$.all', ...chunk.declarators.map(({ init }) => init));
+				const init = b.call(`$.${chunk.type}`, ...chunk.declarators.map(({ init }) => init));
 				body.splice(
 					chunk.position + offset,
 					0,

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

@@ -71,7 +71,8 @@ export function VariableDeclaration(node, context) {
 						];
 						if (
 							context.state.current_parallelized_chunk &&
-							context.state.current_parallelized_chunk.kind === node.kind
+							context.state.current_parallelized_chunk.kind === node.kind &&
+							context.state.current_parallelized_chunk.type === 'all'
 						) {
 							context.state.current_parallelized_chunk.declarators.push(...declarators);
 							context.state.current_parallelized_chunk.bindings.push(...bindings);
@@ -79,11 +80,13 @@ export function VariableDeclaration(node, context) {
 								context.path.at(-1)
 							).body.indexOf(node);
 						} else {
+							/** @type {ParallelizedChunk} */
 							const chunk = {
 								kind: node.kind,
 								declarators,
 								position: /** @type {Program} */ (context.path.at(-1)).body.indexOf(node),
-								bindings
+								bindings,
+								type: 'all'
 							};
 							context.state.current_parallelized_chunk = chunk;
 							context.state.parallelized_chunks.push(chunk);
@@ -257,7 +260,6 @@ export function VariableDeclaration(node, context) {
 					is_async &&
 					context.state.analysis.instance &&
 					context.state.scope === context.state.analysis.instance.scope &&
-					!dev &&
 					// TODO make it work without this
 					declarator.id.type === 'Identifier'
 				) {
@@ -266,6 +268,7 @@ export function VariableDeclaration(node, context) {
 						...context.state.scope.get_bindings(declarator)
 					]);
 				}
+				const type = parallelize ? (dev ? 'promise_all' : 'all') : null;
 
 				/** @type {VariableDeclarator[]} */
 				const derived_declarators = [];
@@ -289,7 +292,13 @@ export function VariableDeclaration(node, context) {
 						);
 
 						if (!parallelize) call = b.call(b.await(b.call('$.save', call)));
-						if (dev) call = b.call('$.tag', call, b.literal(declarator.id.name));
+						if (dev) {
+							call = b.call(
+								'$.tag' + (parallelize ? '_async' : ''),
+								call,
+								b.literal(declarator.id.name)
+							);
+						}
 						bindings.push(/** @type {Binding} */ (context.state.scope.get(declarator.id.name)));
 						derived_declarators.push(b.declarator(declarator.id, call));
 					} else {
@@ -373,7 +382,8 @@ export function VariableDeclaration(node, context) {
 					}));
 					if (
 						context.state.current_parallelized_chunk &&
-						context.state.current_parallelized_chunk.kind === node.kind
+						context.state.current_parallelized_chunk.kind === node.kind &&
+						context.state.current_parallelized_chunk.type === type
 					) {
 						context.state.current_parallelized_chunk.declarators.push(...declarators);
 						context.state.current_parallelized_chunk.bindings.push(...bindings);
@@ -381,11 +391,13 @@ export function VariableDeclaration(node, context) {
 							context.path.at(-1)
 						).body.indexOf(node);
 					} else {
+						/** @type {ParallelizedChunk} */
 						const chunk = {
 							kind: node.kind,
 							declarators,
 							position: /** @type {Program} */ (context.path.at(-1)).body.indexOf(node),
-							bindings
+							bindings,
+							type: /** @type {ParallelizedChunk['type']} */ (type)
 						};
 						context.state.current_parallelized_chunk = chunk;
 						context.state.parallelized_chunks.push(chunk);

packages/svelte/src/internal/client/dev/tracing.js

@@ -184,6 +184,17 @@ export function tag(source, label) {
 	return source;
 }
 
+/**
+ * @template T
+ * @param {Promise<Value<T>>} promise
+ * @param {string} label
+ * @returns {Promise<Value<T>>}
+ */
+export async function tag_async(promise, label) {
+	const source = await promise;
+	return tag(source, label);
+}
+
 /**
  * @param {unknown} value
  * @param {string} label

packages/svelte/src/internal/client/index.js

@@ -7,7 +7,7 @@ export { add_locations } from './dev/elements.js';
 export { hmr } from './dev/hmr.js';
 export { create_ownership_validator } from './dev/ownership.js';
 export { check_target, legacy_api } from './dev/legacy.js';
-export { trace, tag, tag_proxy } from './dev/tracing.js';
+export { trace, tag, tag_async, tag_proxy } from './dev/tracing.js';
 export { inspect } from './dev/inspect.js';
 export { async } from './dom/blocks/async.js';
 export { validate_snippet_args } from './dev/validation.js';
@@ -102,6 +102,7 @@ export {
 	all,
 	async_body,
 	for_await_track_reactivity_loss,
+	promise_all,
 	save,
 	track_reactivity_loss
 } from './reactivity/async.js';

packages/svelte/src/internal/client/reactivity/async.js

@@ -202,3 +202,5 @@ export function all(...promises) {
 		)
 	);
 }
+
+export const promise_all = Promise.all;