tweaks

Author: trueadm

packages/svelte/elements.d.ts

@@ -2028,6 +2028,7 @@ export interface SvelteHTMLElements {
 	'svelte:head': { [name: string]: any };
 	'svelte:boundary': {
 		onerror?: (error: Error, reset: () => void) => void;
+		failed?: import('svelte').Snippet;
 	};
 
 	[name: string]: { [name: string]: any };

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

@@ -1,4 +1,4 @@
-/** @import { BlockStatement, Statement, Pattern, Expression } from 'estree' */
+/** @import { BlockStatement, Statement, Property, Expression } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types' */
 
@@ -11,27 +11,45 @@ export function SvelteBoundary(node, context) {
 	const nodes = [];
 	/** @type {Statement[]} */
 	const snippet_statements = [];
-	/** @type {Expression} */
-	let failed_param = b.literal(null);
-	/** @type {Expression | null} */
-	let onerror = null;
+	/** @type {Array<Property[] | Expression>} */
+	const props_and_spreads = [];
+
+	let has_spread = false;
+
+	const push_prop = (/** @type {Property} */ prop) => {
+		let current = props_and_spreads.at(-1);
+		if (Array.isArray(current)) {
+			current.push(prop);
+		}
+		const arr = [prop];
+		props_and_spreads.push(arr);
+	};
 
 	for (const attribute of node.attributes) {
+		if (attribute.type === 'SpreadAttribute') {
+			has_spread = true;
+			props_and_spreads.push(attribute.expression);
+			continue;
+		}
 		if (
 			attribute.type !== 'Attribute' ||
 			attribute.value === true ||
 			Array.isArray(attribute.value)
 		) {
 			continue;
 		}
-		if (attribute.name === 'onerror') {
-			onerror = /** @type {Expression} */ (
-				context.visit(attribute.value.expression, context.state)
-			);
-		} else if (attribute.name === 'failed') {
-			failed_param = /** @type {Expression} */ (
+		if (attribute.name === 'onerror' || attribute.name === 'failed') {
+			const value = /** @type {Expression} */ (
 				context.visit(attribute.value.expression, context.state)
 			);
+
+			if (attribute.metadata.expression.has_state) {
+				push_prop(
+					b.prop('get', b.id(attribute.name), b.function(null, [], b.block([b.return(value)])))
+				);
+			} else {
+				push_prop(b.prop('init', b.id(attribute.name), value));
+			}
 		}
 	}
 
@@ -41,7 +59,8 @@ export function SvelteBoundary(node, context) {
 			const init = [];
 			const block_state = { ...context.state, init };
 			context.visit(child, block_state);
-			failed_param = b.id('failed');
+			const current = props_and_spreads.at(-1) ?? props_and_spreads.push([]);
+			push_prop(b.prop('init', b.id('failed'), b.id('failed')));
 			snippet_statements.push(...init);
 		} else {
 			nodes.push(child);
@@ -58,14 +77,16 @@ export function SvelteBoundary(node, context) {
 		)
 	);
 
+	const props_expression =
+		!has_spread && Array.isArray(props_and_spreads[0])
+			? b.object(props_and_spreads[0])
+			: b.call(
+					'$.spread_props',
+					...props_and_spreads.map((p) => (Array.isArray(p) ? b.object(p) : p))
+				);
+
 	const boundary = b.stmt(
-		b.call(
-			'$.boundary',
-			context.state.node,
-			b.arrow([b.id('$$anchor')], block),
-			failed_param,
-			!onerror ? b.literal(null) : onerror
-		)
+		b.call('$.boundary', context.state.node, b.arrow([b.id('$$anchor')], block), props_expression)
 	);
 
 	context.state.template.push('<!>');

packages/svelte/src/internal/client/dom/blocks/boundary.js

@@ -43,11 +43,13 @@ function with_boundary(boundary, fn) {
 /**
  * @param {TemplateNode} node
  * @param {((anchor: Node) => void)} boundary_fn
- * @param {(anchor: Node, error: () => Error, reset: () => () => void) => void | null} failed
- * @param {(error: Error, reset: () => void) => void | null} onerror
+ * @param {{
+ * 	 onerror?: (error: Error, reset: () => void) => void,
+ *   failed?: (anchor: Node, error: () => Error, reset: () => () => void) => void
+ * }} props
  * @returns {void}
  */
-export function boundary(node, boundary_fn, failed, onerror) {
+export function boundary(node, boundary_fn, props) {
 	var anchor = node;
 
 	/** @type {Effect | null} */
@@ -67,7 +69,7 @@ export function boundary(node, boundary_fn, failed, onerror) {
 
 			// If we have nothing to capture the error then rethrow the error
 			// for another boundary to handle
-			if (!onerror && !failed) {
+			if (!props.onerror && !props.failed) {
 				throw error;
 			}
 
@@ -82,17 +84,19 @@ export function boundary(node, boundary_fn, failed, onerror) {
 				});
 			};
 
-			if (onerror) {
-				onerror(error, reset);
+			if (props.onerror) {
+				props.onerror(error, reset);
 			}
 
-			if (failed) {
+			let failed_snippet = props.failed;
+
+			if (failed_snippet) {
 				// Ensure we create the boundary branch after the catch event cycle finishes
 				queue_micro_task(() => {
 					with_boundary(boundary, () => {
 						boundary_effect = null;
 						boundary_effect = branch(() =>
-							failed(
+							failed_snippet(
 								anchor,
 								() => error,
 								() => reset