hoist functions, use names to make stuff a little clearer

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

@@ -83,7 +83,10 @@ export function boundary(node, props, boundary_fn) {
 		var hydrate_open = hydrate_node;
 		var is_creating_fallback = false;
 
-		var render_snippet = (/** @type { () => void } */ snippet_fn) => {
+		/**
+		 * @param {() => void} snippet_fn
+		 */
+		function render_snippet(snippet_fn) {
 			with_boundary(boundary, () => {
 				is_creating_fallback = true;
 
@@ -98,15 +101,9 @@ export function boundary(node, props, boundary_fn) {
 				reset_is_throwing_error();
 				is_creating_fallback = false;
 			});
-		};
+		}
-
-		// @ts-ignore We re-use the effect's fn property to avoid allocation of an additional field
-		boundary.fn = (/** @type {unknown} */ input) => {
-			let pending = /** @type {(anchor: Node) => void} */ (props.pending);
 
-			if (input === ASYNC_INCREMENT) {
+		function suspend() {
-				if (async_count++ === 0) {
-					queue_boundary_micro_task(() => {
 			if (async_effect || !boundary_effect) {
 				return;
 			}
@@ -135,32 +132,56 @@ export function boundary(node, props, boundary_fn) {
 				false
 			);
 
+			const pending = props.pending;
+
+			if (pending) {
 				render_snippet(() => {
 					pending(anchor);
 				});
-					});
 			}
-
-				return true;
 		}
 
-			if (input === ASYNC_DECREMENT) {
+		function unsuspend() {
-				if (--async_count === 0) {
-					queue_boundary_micro_task(() => {
 			if (!async_effect) {
 				return;
 			}
+
 			if (boundary_effect) {
 				destroy_effect(boundary_effect);
 			}
+
 			boundary_effect = async_effect;
 			async_effect = null;
 			anchor.before(/** @type {DocumentFragment} */ (async_fragment));
 			resume_effect(boundary_effect);
+		}
+
+		function reset() {
+			pause_effect(boundary_effect);
+
+			with_boundary(boundary, () => {
+				is_creating_fallback = false;
+				boundary_effect = branch(() => boundary_fn(anchor));
+				reset_is_throwing_error();
 			});
 		}
 
-				return true;
+		// @ts-ignore We re-use the effect's fn property to avoid allocation of an additional field
+		boundary.fn = (/** @type {unknown} */ input) => {
+			if (input === ASYNC_INCREMENT) {
+				if (async_count++ === 0) {
+					queue_boundary_micro_task(suspend);
+				}
+
+				return;
+			}
+
+			if (input === ASYNC_DECREMENT) {
+				if (--async_count === 0) {
+					queue_boundary_micro_task(unsuspend);
+				}
+
+				return;
 			}
 
 			var error = input;
@@ -169,20 +190,10 @@ export function boundary(node, props, boundary_fn) {
 
 			// If we have nothing to capture the error, or if we hit an error while
 			// rendering the fallback, re-throw for another boundary to handle
-			if ((!onerror && !failed) || is_creating_fallback) {
+			if (is_creating_fallback || (!onerror && !failed)) {
 				throw error;
 			}
 
-			var reset = () => {
-				pause_effect(boundary_effect);
-
-				with_boundary(boundary, () => {
-					is_creating_fallback = false;
-					boundary_effect = branch(() => boundary_fn(anchor));
-					reset_is_throwing_error();
-				});
-			};
-
 			onerror?.(error, reset);
 
 			if (boundary_effect) {