diff --git a/src/cdk/tree/tree.spec.ts b/src/cdk/tree/tree.spec.ts
index 7298996a0e14..b02221f5b9d5 100644
--- a/src/cdk/tree/tree.spec.ts
+++ b/src/cdk/tree/tree.spec.ts
@@ -2183,6 +2183,6 @@ class NestedChildrenExpansionTest {
     data[0].children = children;
 
     this.dataSource = data;
-    this.allNodes = [...data, ...children, ... nestedChildren];
+    this.allNodes = [...data, ...children, ...nestedChildren];
   }
 }
diff --git a/src/cdk/tree/tree.ts b/src/cdk/tree/tree.ts
index 9260fb875ab0..121cb0a16c47 100644
--- a/src/cdk/tree/tree.ts
+++ b/src/cdk/tree/tree.ts
@@ -273,18 +273,21 @@ export class CdkTree<T, K = T>
 
   constructor(...args: unknown[]);
   constructor() {
-    effect(onCleanup => {
-      const data = this._data();
-      const nodeType = this._nodeType();
-      const expandedKeys = this._selection();
-
-      const sub = this._getRenderData(data, nodeType, expandedKeys).subscribe(renderData => {
-        this._renderDataChanges(renderData);
-      });
-      onCleanup(() => {
-        sub.unsubscribe();
-      });
-    }, {allowSignalWrites: true});
+    effect(
+      onCleanup => {
+        const data = this._data();
+        const nodeType = this._nodeType();
+        const expandedKeys = this._selection();
+
+        const sub = this._getRenderData(data, nodeType, expandedKeys).subscribe(renderData => {
+          this._renderDataChanges(renderData);
+        });
+        onCleanup(() => {
+          sub.unsubscribe();
+        });
+      },
+      {allowSignalWrites: true},
+    );
   }
 
   ngAfterContentInit() {
@@ -1004,7 +1007,11 @@ export class CdkTree<T, K = T>
    * This will still traverse all nested children in order to build up our internal data
    * models, but will not include them in the returned array.
    */
-  private _flattenNestedNodesWithExpansion(nodes: readonly T[], selection: readonly K[], level = 0): Observable<T[]> {
+  private _flattenNestedNodesWithExpansion(
+    nodes: readonly T[],
+    selection: readonly K[],
+    level = 0,
+  ): Observable<T[]> {
     const childrenAccessor = this._getChildrenAccessor();
     // If we're using a level accessor, we don't need to flatten anything.
     if (!childrenAccessor) {
@@ -1037,7 +1044,7 @@ export class CdkTree<T, K = T>
                 return observableOf([]);
               }
               return this._flattenNestedNodesWithExpansion(childNodes, selection, level + 1).pipe(
-                map(nestedNodes => selection.includes(parentKey) ? nestedNodes : []),
+                map(nestedNodes => (selection.includes(parentKey) ? nestedNodes : [])),
               );
             }),
           ),