memoize clsx

Author: adiguba

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

@@ -573,14 +573,17 @@ function build_element_attribute_update_assignment(
 
 	const is_autofocus = name === 'autofocus';
 
-	let { value, has_state } = build_attribute_value(attribute.value, context, (value, metadata) =>
-		metadata.has_call
-			? // if it's autofocus we will not add this to a template effect so we don't want to get the expression id
-				// but separately memoize the expression
-				is_autofocus
-				? memoize_expression(state, value)
-				: get_expression_id(state, value)
-			: value
+	let { value, has_state, has_call } = build_attribute_value(
+		attribute.value,
+		context,
+		(value, metadata) =>
+			metadata.has_call
+				? // if it's autofocus we will not add this to a template effect so we don't want to get the expression id
+					// but separately memoize the expression
+					is_autofocus
+					? memoize_expression(state, value)
+					: get_expression_id(state, value)
+				: value
 	);
 
 	if (is_autofocus) {
@@ -608,6 +611,7 @@ function build_element_attribute_update_assignment(
 			attribute,
 			value,
 			has_state,
+			has_call,
 			class_directives,
 			context,
 			!is_svg && !is_mathml

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

@@ -87,7 +87,7 @@ export function SvelteElement(node, context) {
 		is_text_attribute(attributes[0])
 	) {
 		// special case when there only a class attribute, without call expression
-		let { value, has_state } = build_attribute_value(
+		let { value, has_state, has_call } = build_attribute_value(
 			attributes[0].value,
 			context,
 			(value, metadata) => (metadata.has_call ? get_expression_id(context.state, value) : value)
@@ -99,6 +99,7 @@ export function SvelteElement(node, context) {
 			attributes[0],
 			value,
 			has_state,
+			has_call,
 			class_directives,
 			inner_context,
 			false

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

@@ -155,25 +155,26 @@ export function build_style_directives(
  * @param {AST.Attribute['value']} value
  * @param {ComponentContext} context
  * @param {(value: Expression, metadata: ExpressionMetadata) => Expression} memoize
- * @returns {{ value: Expression, has_state: boolean }}
+ * @returns {{ value: Expression, has_state: boolean, has_call: boolean }}
  */
 export function build_attribute_value(value, context, memoize = (value) => value) {
 	if (value === true) {
-		return { value: b.literal(true), has_state: false };
+		return { value: b.literal(true), has_state: false, has_call: false };
 	}
 
 	if (!Array.isArray(value) || value.length === 1) {
 		const chunk = Array.isArray(value) ? value[0] : value;
 
 		if (chunk.type === 'Text') {
-			return { value: b.literal(chunk.data), has_state: false };
+			return { value: b.literal(chunk.data), has_state: false, has_call: false };
 		}
 
 		let expression = /** @type {Expression} */ (context.visit(chunk.expression));
 
 		return {
 			value: memoize(expression, chunk.metadata.expression),
-			has_state: chunk.metadata.expression.has_state
+			has_state: chunk.metadata.expression.has_state,
+			has_call: chunk.metadata.expression.has_call
 		};
 	}
 
@@ -198,6 +199,7 @@ export function get_attribute_name(element, attribute) {
  * @param {AST.Attribute | null} attribute
  * @param {Expression} value
  * @param {boolean} has_state
+ * @param {boolean} has_call
  * @param {AST.ClassDirective[]} class_directives
  * @param {ComponentContext} context
  * @param {boolean} is_html
@@ -209,12 +211,16 @@ export function build_set_class(
 	attribute,
 	value,
 	has_state,
+	has_call,
 	class_directives,
 	context,
 	is_html
 ) {
 	if (attribute && attribute.metadata.needs_clsx) {
 		value = b.call('$.clsx', value);
+		if (has_state && !has_call) {
+			value = get_expression_id(context.state, value);
+		}
 	}
 
 	/** @type {Identifier | undefined} */

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

@@ -80,7 +80,7 @@ function compare_expressions(a, b) {
  * @param {(node: AST.SvelteNode, state: any) => any} visit
  * @param {ComponentClientTransformState} state
  * @param {(value: Expression, metadata: ExpressionMetadata) => Expression} memoize
- * @returns {{ value: Expression, has_state: boolean }}
+ * @returns {{ value: Expression, has_state: boolean, has_call: boolean }}
  */
 export function build_template_chunk(
 	values,
@@ -95,6 +95,7 @@ export function build_template_chunk(
 	const quasis = [quasi];
 
 	let has_state = false;
+	let has_call = false;
 
 	for (let i = 0; i < values.length; i++) {
 		const node = values[i];
@@ -116,11 +117,12 @@ export function build_template_chunk(
 			);
 
 			has_state ||= node.metadata.expression.has_state;
+			has_call ||= node.metadata.expression.has_call;
 
 			if (values.length === 1) {
 				// If we have a single expression, then pass that in directly to possibly avoid doing
 				// extra work in the template_effect (instead we do the work in set_text).
-				return { value, has_state };
+				return { value, has_state, has_call };
 			}
 
 			if (
@@ -162,7 +164,7 @@ export function build_template_chunk(
 			? b.template(quasis, expressions)
 			: b.literal(/** @type {string} */ (quasi.value.cooked));
 
-	return { value, has_state };
+	return { value, has_state, has_call };
 }
 
 /**