From fee4ca129c18a2a64db06f801059e994e1a03104 Mon Sep 17 00:00:00 2001
From: Marin Atanasov <8436925+tyxla@users.noreply.github.com>
Date: Mon, 25 Sep 2023 19:45:22 +0300
Subject: [PATCH] core-data: Fix nested property access with undefined name
 (#54790)

* core-data: Fix nested property access with undefined name

* Add a unit test
---
 .../core-data/src/queried-data/selectors.js   |  2 +-
 packages/core-data/src/selectors.ts           |  2 +-
 packages/core-data/src/test/selectors.js      | 37 +++++++++++++++++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/packages/core-data/src/queried-data/selectors.js b/packages/core-data/src/queried-data/selectors.js
index a3e6f322274ced..562aab7ce6b79b 100644
--- a/packages/core-data/src/queried-data/selectors.js
+++ b/packages/core-data/src/queried-data/selectors.js
@@ -68,7 +68,7 @@ function getQueriedItemsUncached( state, query ) {
 				const field = fields[ f ].split( '.' );
 				let value = item;
 				field.forEach( ( fieldName ) => {
-					value = value[ fieldName ];
+					value = value?.[ fieldName ];
 				} );
 
 				setNestedValue( filteredItem, field, value );
diff --git a/packages/core-data/src/selectors.ts b/packages/core-data/src/selectors.ts
index 7d6cbeb4daeee9..34445f73d2e60a 100644
--- a/packages/core-data/src/selectors.ts
+++ b/packages/core-data/src/selectors.ts
@@ -344,7 +344,7 @@ export const getEntityRecord = createSelector(
 				const field = fields[ f ].split( '.' );
 				let value = item;
 				field.forEach( ( fieldName ) => {
-					value = value[ fieldName ];
+					value = value?.[ fieldName ];
 				} );
 				setNestedValue( filteredItem, field, value );
 			}
diff --git a/packages/core-data/src/test/selectors.js b/packages/core-data/src/test/selectors.js
index 161d0af4ea5bca..5ae7a81fa144e9 100644
--- a/packages/core-data/src/test/selectors.js
+++ b/packages/core-data/src/test/selectors.js
@@ -135,6 +135,43 @@ describe.each( [
 			} )
 		).toEqual( { content: 'chicken' } );
 	} );
+
+	it( 'should work well for nested fields properties', () => {
+		const state = deepFreeze( {
+			entities: {
+				records: {
+					root: {
+						postType: {
+							queriedData: {
+								items: {
+									default: {
+										post: {
+											foo: undefined,
+										},
+									},
+								},
+								itemIsComplete: {
+									default: {
+										post: true,
+									},
+								},
+								queries: {},
+							},
+						},
+					},
+				},
+			},
+		} );
+		expect(
+			getEntityRecord( state, 'root', 'postType', 'post', {
+				_fields: [ 'foo.bar' ],
+			} )
+		).toEqual( {
+			foo: {
+				bar: undefined,
+			},
+		} );
+	} );
 } );
 
 describe( 'hasEntityRecords', () => {