Data: Avoid tracking itemIds while request in progress

WordPress · May 4, 2018 · fda0520 · fda0520
1 parent 1e599cb
commit fda0520
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Showing 4 changed files with 35 additions and 5 deletions.
diff --git a/core-data/queried-data/reducer.js b/core-data/queried-data/reducer.js
@@ -29,7 +29,7 @@ import getQueryParts from './get-query-parts';
  *
  * @return {number[]} Merged array of item IDs.
  */
-export function getMergedItemIds( itemIds = [], nextItemIds, page, perPage ) {
+export function getMergedItemIds( itemIds, nextItemIds, page, perPage ) {
 	const nextItemIdsStartIndex = ( page - 1 ) * perPage;
 
 	// If later page has already been received, default to the larger known
@@ -125,15 +125,15 @@ const queries = flowRight( [
 	// for default query on initialization.
 	withReturnUndefinedOnUnhandledDefault,
 ] )( combineReducers( {
-	itemIds( state = [], action ) {
+	itemIds( state = null, action ) {
 		const { type, page, perPage } = action;
 
 		if ( type !== RECEIVE_ITEMS ) {
 			return state;
 		}
 
 		return getMergedItemIds(
-			state,
+			state || [],
 			map( action.items, 'id' ),
 			page,
 			perPage

diff --git a/core-data/queried-data/selectors.js b/core-data/queried-data/selectors.js
@@ -46,6 +46,10 @@ export function getQueriedItems( state, query ) {
 	}
 
 	const itemIds = state.queries[ stableKey ].itemIds;
+	if ( ! itemIds ) {
+		return null;
+	}
+
 	const startOffset = ( page - 1 ) * perPage;
 	const endOffset = startOffset + perPage;
 

diff --git a/core-data/queried-data/test/reducer.js b/core-data/queried-data/test/reducer.js
@@ -16,7 +16,7 @@ import reducer, {
 
 describe( 'getMergedItemIds', () => {
 	it( 'should receive a page', () => {
-		const result = getMergedItemIds( undefined, [ 4, 5, 6 ], 2, 3 );
+		const result = getMergedItemIds( [], [ 4, 5, 6 ], 2, 3 );
 
 		expect( result ).toEqual( [
 			undefined,
@@ -164,7 +164,7 @@ describe( 'reducer', () => {
 			items: {},
 			queries: {
 				'': {
-					itemIds: [],
+					itemIds: null,
 					requestingPageByPerPage: {
 						10: {
 							1: true,

diff --git a/core-data/queried-data/test/selectors.js b/core-data/queried-data/test/selectors.js
@@ -0,0 +1,26 @@
+/**
+ * Internal dependencies
+ */
+import { getQueriedItems } from '../selectors';
+
+describe( 'getQueriedItems', () => {
+	it( 'should return null if requesting but no item IDs', () => {
+		const state = {
+			items: {},
+			queries: {
+				'': {
+					itemIds: null,
+					requestingPageByPerPage: {
+						10: {
+							1: true,
+						},
+					},
+				},
+			},
+		};
+
+		const result = getQueriedItems( state );
+
+		expect( result ).toBe( null );
+	} );
+} );