diff --git a/src/compiler/compile/render_ssr/handlers/utils/remove_whitespace_children.ts b/src/compiler/compile/render_ssr/handlers/utils/remove_whitespace_children.ts
index c013394be3..433af27a05 100644
--- a/src/compiler/compile/render_ssr/handlers/utils/remove_whitespace_children.ts
+++ b/src/compiler/compile/render_ssr/handlers/utils/remove_whitespace_children.ts
@@ -1,75 +1,83 @@
-import { INode } from '../../../nodes/interfaces';
-import { trim_end, trim_start } from '../../../../utils/trim';
+import { trim_end, trim_start } from '../../../../utils/trim.js';
 import { link } from '../../../../utils/link';
 import { regex_starts_with_whitespace } from '../../../../utils/patterns';
-
 // similar logic from `compile/render_dom/wrappers/Fragment`
 // We want to remove trailing whitespace inside an element/component/block,
 // *unless* there is no whitespace between this node and its next sibling
-export default function remove_whitespace_children(children: INode[], next?: INode): INode[] {
-	const nodes: INode[] = [];
-	let last_child: INode;
-	let i = children.length;
-	while (i--) {
-		const child = children[i];
-
-		if (child.type === 'Text') {
-			if (child.should_skip()) {
-				continue;
-			}
 
-			let { data } = child;
+/**
+ * @param {INode[]} children
+ * @param {import('../../../nodes/interfaces.js').INode} [next]
+ * @returns {INode[]}
+ */
+export default function remove_whitespace_children(children, next) {
 
-			if (nodes.length === 0) {
-				const should_trim = next
-					? next.type === 'Text' &&
-					  regex_starts_with_whitespace.test(next.data) &&
-					  trimmable_at(child, next)
-					: !child.has_ancestor('EachBlock');
+    /** @type {INode[]} */
+    const nodes = [];
 
-				if (should_trim && !child.keep_space()) {
-					data = trim_end(data);
-					if (!data) continue;
-				}
-			}
-
-			// glue text nodes (which could e.g. be separated by comments) together
-			if (last_child && last_child.type === 'Text') {
-				last_child.data = data + last_child.data;
-				continue;
-			}
+    /** @type {import('../../../nodes/interfaces.js').INode} */
+    let last_child;
+    let i = children.length;
+    while (i--) {
+        const child = children[i];
+        if (child.type === 'Text') {
+            if (child.should_skip()) {
+                continue;
+            }
+            let { data } = child;
+            if (nodes.length === 0) {
+                const should_trim = next
+                    ? next.type === 'Text' &&
+                        regex_starts_with_whitespace.test(next.data) &&
+                        trimmable_at(child, next)
+                    : !child.has_ancestor('EachBlock');
+                if (should_trim && !child.keep_space()) {
+                    data = trim_end(data);
+                    if (!data)
+                        continue;
+                }
+            }
+            // glue text nodes (which could e.g. be separated by comments) together
+            if (last_child && last_child.type === 'Text') {
+                last_child.data = data + last_child.data;
+                continue;
+            }
+            child.data = data;
+            nodes.unshift(child);
+            link(last_child, (last_child = child));
+        }
+        else {
+            nodes.unshift(child);
+            link(last_child, (last_child = child));
+        }
+    }
+    const first = nodes[0];
+    if (first && first.type === 'Text' && !first.keep_space()) {
+        first.data = trim_start(first.data);
+        if (!first.data) {
+            first.var = null;
+            nodes.shift();
+            if (nodes[0]) {
+                nodes[0].prev = null;
+            }
+        }
+    }
+    return nodes;
+}
 
-			child.data = data;
-			nodes.unshift(child);
-			link(last_child, (last_child = child));
-		} else {
-			nodes.unshift(child);
-			link(last_child, (last_child = child));
-		}
-	}
+/**
+ * @param {import('../../../nodes/interfaces.js').INode} child
+ * @param {import('../../../nodes/interfaces.js').INode} next_sibling
+ * @returns {boolean}
+ */
+function trimmable_at(child, next_sibling) {
+    // Whitespace is trimmable if one of the following is true:
+    // The child and its sibling share a common nearest each block (not at an each block boundary)
+    // The next sibling's previous node is an each block
+    return (next_sibling.find_nearest(/EachBlock/) === child.find_nearest(/EachBlock/) ||
+        next_sibling.prev.type === 'EachBlock');
+}
 
-	const first = nodes[0];
-	if (first && first.type === 'Text' && !first.keep_space()) {
-		first.data = trim_start(first.data);
-		if (!first.data) {
-			first.var = null;
-			nodes.shift();
 
-			if (nodes[0]) {
-				nodes[0].prev = null;
-			}
-		}
-	}
 
-	return nodes;
-}
 
-function trimmable_at(child: INode, next_sibling: INode): boolean {
-	// Whitespace is trimmable if one of the following is true:
-	// The child and its sibling share a common nearest each block (not at an each block boundary)
-	// The next sibling's previous node is an each block
-	return (
-		next_sibling.find_nearest(/EachBlock/) === child.find_nearest(/EachBlock/) ||
-		next_sibling.prev.type === 'EachBlock'
-	);
-}