diff --git a/index.d.ts b/index.d.ts
index 73667b4..88ec3d5 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -3,8 +3,10 @@
 
 import * as React from 'react';
 
+type NodeId = number | string;
+
 interface BasicNode {
-  id: number | string;
+  id: NodeId;
   name: string;
   state?: {[stateKey: string]: any};
 }
@@ -94,7 +96,7 @@ interface GroupRendererProps {
 }
 
 export interface FilteringContainerProps {
-  children: (nodes: Node[]) => JSX.Element;
+  children: (params: {nodes: Node[]; nodeParentMappings: {[id: NodeId]: NodeId[]}}) => JSX.Element;
   debouncer?: (func: (...p: any[]) => any, timeout: number) => void;
   groups?: {[g: string]: Group};
   selectedGroup?: string;
diff --git a/src/FilteringContainer.js b/src/FilteringContainer.js
index f518a0a..701fc2b 100644
--- a/src/FilteringContainer.js
+++ b/src/FilteringContainer.js
@@ -65,7 +65,7 @@ export default class FilteringContainer extends React.Component {
     const relevantNodes =
       groups && selectedGroup && groups[selectedGroup]
         ? filterNodes(groups[selectedGroup].filter, nodes)
-        : {nodes, nodeParentMappings: []};
+        : {nodes, nodeParentMappings: {}};
 
     const {nodes: filteredNodes, nodeParentMappings} = filterTerm
       ? filterNodes(nameMatchesSearchTerm(filterTerm), relevantNodes.nodes)