fix(entityAdapter): ensure sorted setMany keeps just unique IDs in state.ids

packages/toolkit/src/entities/sorted_state_adapter.ts

@@ -93,11 +93,16 @@ export function createSortedStateAdapter<T, Id extends EntityId>(
     newEntities: readonly T[] | Record<Id, T>,
     state: R,
   ): void {
+    let deduplicatedEntities = {} as Record<Id, T>;
     newEntities = ensureEntitiesArray(newEntities)
     if (newEntities.length !== 0) {
       for (const item of newEntities) {
-        delete (state.entities as Record<Id, T>)[selectId(item)]
+        const entityId = selectId(item);
+        // For multiple items with the same ID, we should keep the last one.
+        deduplicatedEntities[entityId] = item;
+        delete (state.entities as Record<Id, T>)[entityId]
       }
+      newEntities = ensureEntitiesArray(deduplicatedEntities);
       mergeFunction(state, newEntities)
     }
   }

packages/toolkit/src/entities/tests/sorted_state_adapter.test.ts

@@ -607,6 +607,25 @@ describe('Sorted State Adapter', () => {
     expect(withOneSorted).toEqual(withOneUnsorted);
   })
 
+  it('should work consistent with Unsorted State Adapter adding duplicate ids', () => {
+    const unsortedAdaptor = createEntityAdapter({
+      selectId: (book: BookModel) => book.id
+    });
+
+    const firstEntry = {id: AClockworkOrange.id, author: TheHobbit.author }
+    const secondEntry = {id: AClockworkOrange.id, title: 'Zack' }
+    const withNothingSorted = adapter.setAll(state, [TheHobbit]);
+    const withNothingUnsorted = unsortedAdaptor.setAll(state, [TheHobbit]);
+    const withOneSorted = adapter.setMany(withNothingSorted, [
+      { ...AClockworkOrange, ...firstEntry, id: 'th' }, {...AClockworkOrange, ...secondEntry, id: 'th'}
+    ])
+    const withOneUnsorted = unsortedAdaptor.setMany(withNothingUnsorted, [
+      { ...AClockworkOrange, ...firstEntry, id: 'th' }, {...AClockworkOrange, ...secondEntry, id: 'th'}
+    ])
+
+    expect(withOneSorted).toEqual(withOneUnsorted);
+  })
+
   it('should let you set many entities in the state when passing in a dictionary', () => {
     const changeWithoutAuthor = { id: TheHobbit.id, title: 'Silmarillion' }
     const withMany = adapter.setAll(state, [TheHobbit])