diff --git a/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/directive-forest/component-data-source.ts b/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/directive-forest/component-data-source.ts
index f7fd00629f0..619e554df28 100644
--- a/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/directive-forest/component-data-source.ts
+++ b/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/directive-forest/component-data-source.ts
@@ -4,7 +4,7 @@ import { BehaviorSubject, merge, Observable } from 'rxjs';
 import { MatTreeFlattener } from '@angular/material/tree';
 import { FlatTreeControl } from '@angular/cdk/tree';
 import { map } from 'rxjs/operators';
-import { DefaultIterableDiffer } from '@angular/core';
+import { DefaultIterableDiffer, TrackByFunction } from '@angular/core';
 import { IndexedNode, indexForest } from './index-forest';
 import { diff } from '../../diffing';
 
@@ -22,7 +22,7 @@ export interface FlatNode {
 
 const expandable = (node: IndexedNode) => !!node.children && node.children.length > 0;
 
-const trackBy = (_: number, item: FlatNode) => `${item.id}#${item.expandable}`;
+const trackBy: TrackByFunction<FlatNode> = (_: number, item: FlatNode) => `${item.id}#${item.expandable}`;
 
 const getId = (node: IndexedNode) => {
   let prefix = '';
@@ -61,7 +61,7 @@ const filterCommentNodes = (nodes: IndexedNode[]) => {
 };
 
 export class ComponentDataSource extends DataSource<FlatNode> {
-  private _differ = new DefaultIterableDiffer(trackBy);
+  private _differ = new DefaultIterableDiffer<FlatNode>(trackBy);
   private _expandedData = new BehaviorSubject<FlatNode[]>([]);
   private _flattenedData = new BehaviorSubject<FlatNode[]>([]);
   private _nodeToFlat = new WeakMap<IndexedNode, FlatNode>();
diff --git a/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/property-resolver/property-data-source.ts b/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/property-resolver/property-data-source.ts
index 0c58a25e53e..5e00f8e2306 100644
--- a/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/property-resolver/property-data-source.ts
+++ b/projects/ng-devtools/src/lib/devtools-tabs/directive-explorer/property-resolver/property-data-source.ts
@@ -4,18 +4,19 @@ import { BehaviorSubject, merge, Observable, Subscription } from 'rxjs';
 import { MatTreeFlattener } from '@angular/material/tree';
 import { FlatTreeControl } from '@angular/cdk/tree';
 import { map } from 'rxjs/operators';
-import { DefaultIterableDiffer } from '@angular/core';
+import { DefaultIterableDiffer, TrackByFunction } from '@angular/core';
 import { diff } from '../../diffing';
 import { FlatNode, Property } from './element-property-resolver';
 import { arrayifyProps } from './arrayify-props';
 
-const trackBy = (_: number, item: FlatNode) => `#${item.prop.name}#${item.prop.descriptor.preview}#${item.level}`;
+const trackBy: TrackByFunction<FlatNode> = (_: number, item: FlatNode) =>
+  `#${item.prop.name}#${item.prop.descriptor.preview}#${item.level}`;
 
 export class PropertyDataSource extends DataSource<FlatNode> {
   private _data = new BehaviorSubject<FlatNode[]>([]);
   private _subscriptions: Subscription[] = [];
   private _expandedData = new BehaviorSubject<FlatNode[]>([]);
-  private _differ = new DefaultIterableDiffer(trackBy);
+  private _differ = new DefaultIterableDiffer<FlatNode>(trackBy);
 
   constructor(
     props: { [prop: string]: Descriptor },