simplify

Author: Rich-Harris

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

@@ -1,4 +1,4 @@
-/** @import { ArrowFunctionExpression, AssignmentExpression, Expression, FunctionDeclaration, FunctionExpression, Identifier, Node, Pattern, UpdateExpression } from 'estree' */
+/** @import { ArrowFunctionExpression, AssignmentExpression, BlockStatement, Expression, FunctionDeclaration, FunctionExpression, Identifier, Node, Pattern, UpdateExpression } from 'estree' */
 /** @import { Binding } from '#compiler' */
 /** @import { ClientTransformState, ComponentClientTransformState, ComponentContext } from './types.js' */
 /** @import { Analysis } from '../../types.js' */
@@ -289,20 +289,15 @@ export function should_proxy(node, scope) {
 /**
  * Svelte legacy mode should use safe equals in most places, runes mode shouldn't
  * @param {ComponentClientTransformState} state
- * @param {Expression} arg
+ * @param {Expression | BlockStatement} expression
  * @param {boolean} [async]
  */
-export function create_derived(state, arg, async = false) {
+export function create_derived(state, expression, async = false) {
+	const thunk = b.thunk(expression, async);
+
 	if (async) {
-		return b.call(
-			b.await(
-				b.call(
-					'$.save',
-					b.call('$.async_derived', arg.type === 'ArrowFunctionExpression' ? b.async(arg) : arg)
-				)
-			)
-		);
+		return b.call(b.await(b.call('$.save', b.call('$.async_derived', thunk))));
 	} else {
-		return b.call(state.analysis.runes ? '$.derived' : '$.derived_safe_equal', arg);
+		return b.call(state.analysis.runes ? '$.derived' : '$.derived_safe_equal', thunk);
 	}
 }

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

@@ -96,13 +96,13 @@ function create_derived_block_argument(node, context) {
 		b.return(b.object(identifiers.map((identifier) => b.prop('init', identifier, identifier))))
 	]);
 
-	const declarations = [b.var(value, create_derived(context.state, b.thunk(block)))];
+	const declarations = [b.var(value, create_derived(context.state, block))];
 
 	for (const id of identifiers) {
 		context.state.transform[id.name] = { read: get_value };
 
 		declarations.push(
-			b.var(id, create_derived(context.state, b.thunk(b.member(b.call('$.get', value), id))))
+			b.var(id, create_derived(context.state, b.member(b.call('$.get', value), id)))
 		);
 	}
 

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

@@ -21,11 +21,8 @@ export function ConstTag(node, context) {
 			declaration.init,
 			node.metadata.expression
 		);
-		let expression = create_derived(
-			context.state,
-			b.thunk(init),
-			node.metadata.expression.has_await
-		);
+
+		let expression = create_derived(context.state, init, node.metadata.expression.has_await);
 
 		if (dev) {
 			expression = b.call('$.tag', expression, b.literal(declaration.id.name));
@@ -65,15 +62,13 @@ export function ConstTag(node, context) {
 			declaration.init,
 			node.metadata.expression
 		);
-		const fn = b.arrow(
-			[],
-			b.block([
-				b.const(/** @type {Pattern} */ (context.visit(declaration.id, child_state)), init),
-				b.return(b.object(identifiers.map((node) => b.prop('init', node, node))))
-			])
-		);
 
-		let expression = create_derived(context.state, fn, node.metadata.expression.has_await);
+		const block = b.block([
+			b.const(/** @type {Pattern} */ (context.visit(declaration.id, child_state)), init),
+			b.return(b.object(identifiers.map((node) => b.prop('init', node, node))))
+		]);
+
+		let expression = create_derived(context.state, block, node.metadata.expression.has_await);
 
 		if (dev) {
 			expression = b.call('$.tag', expression, b.literal('[@const]'));

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

@@ -46,9 +46,6 @@ export function LetDirective(node, context) {
 			read: (node) => b.call('$.get', node)
 		};
 
-		return b.const(
-			name,
-			create_derived(context.state, b.thunk(b.member(b.id('$$slotProps'), node.name)))
-		);
+		return b.const(name, create_derived(context.state, b.member(b.id('$$slotProps'), node.name)));
 	}
 }

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

@@ -81,7 +81,7 @@ export function SnippetBlock(node, context) {
 		? b.call(
 				'$.wrap_snippet',
 				b.id(context.state.analysis.name),
-				has_await ? b.async(b.function(null, args, body)) : b.function(null, args, body)
+				b.function(null, args, body, has_await)
 			)
 		: b.arrow(args, body, has_await);
 

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

@@ -588,14 +588,14 @@ export function method(kind, key, params, body, computed = false, is_static = fa
  * @param {ESTree.BlockStatement} body
  * @returns {ESTree.FunctionExpression}
  */
-function function_builder(id, params, body) {
+function function_builder(id, params, body, async = false) {
 	return {
 		type: 'FunctionExpression',
 		id,
 		params,
 		body,
 		generator: false,
-		async: false,
+		async,
 		metadata: /** @type {any} */ (null) // should not be used by codegen
 	};
 }