Add second parameter to getInitialState to prefill entities

Author: EskiMojo14

packages/toolkit/src/entities/create_adapter.ts

@@ -42,11 +42,11 @@ export function createEntityAdapter<T>(
     ...options,
   }
 
-  const stateFactory = createInitialStateFactory<T, EntityId>()
-  const selectorsFactory = createSelectorsFactory<T, EntityId>()
   const stateAdapter = sortComparer
     ? createSortedStateAdapter(selectId, sortComparer)
     : createUnsortedStateAdapter(selectId)
+  const stateFactory = createInitialStateFactory({ stateAdapter })
+  const selectorsFactory = createSelectorsFactory<T, EntityId>()
 
   return {
     selectId,

packages/toolkit/src/entities/entity_state.ts

@@ -1,4 +1,9 @@
-import type { EntityId, EntityState } from './models'
+import type {
+  EntityId,
+  EntityState,
+  EntityStateAdapter,
+  EntityStateFactory,
+} from './models'
 
 export function getInitialEntityState<T, Id extends EntityId>(): EntityState<
   T,
@@ -10,13 +15,25 @@ export function getInitialEntityState<T, Id extends EntityId>(): EntityState<
   }
 }
 
-export function createInitialStateFactory<T, Id extends EntityId>() {
-  function getInitialState(): EntityState<T, Id>
+export function createInitialStateFactory<T, Id extends EntityId>({
+  stateAdapter,
+}: {
+  stateAdapter: EntityStateAdapter<T, Id>
+}): EntityStateFactory<T, Id> {
+  function getInitialState(
+    state?: undefined,
+    entities?: readonly T[] | Record<Id, T>,
+  ): EntityState<T, Id>
   function getInitialState<S extends object>(
     additionalState: S,
+    entities?: readonly T[] | Record<Id, T>,
   ): EntityState<T, Id> & S
-  function getInitialState(additionalState: any = {}): any {
-    return Object.assign(getInitialEntityState(), additionalState)
+  function getInitialState(
+    additionalState: any = {},
+    entities?: readonly T[] | Record<Id, T>,
+  ): any {
+    const state = Object.assign(getInitialEntityState(), additionalState)
+    return entities ? stateAdapter.setAll(state, entities) : state
   }
 
   return { getInitialState }

packages/toolkit/src/entities/models.ts

@@ -166,15 +166,25 @@ export interface EntitySelectors<T, V, Id extends EntityId> {
   selectById: (state: V, id: Id) => Compute<UncheckedIndexedAccess<T>>
 }
 
+export interface EntityStateFactory<T, Id extends EntityId> {
+  getInitialState(
+    state?: undefined,
+    entities?: Record<Id, T> | readonly T[],
+  ): EntityState<T, Id>
+  getInitialState<S extends object>(
+    state: S,
+    entities?: Record<Id, T> | readonly T[],
+  ): EntityState<T, Id> & S
+}
+
 /**
  * @public
  */
 export interface EntityAdapter<T, Id extends EntityId>
-  extends EntityStateAdapter<T, Id> {
+  extends EntityStateAdapter<T, Id>,
+    EntityStateFactory<T, Id> {
   selectId: IdSelector<T, Id>
   sortComparer: false | Comparer<T>
-  getInitialState(): EntityState<T, Id>
-  getInitialState<S extends object>(state: S): EntityState<T, Id> & S
   getSelectors(
     selectState?: undefined,
     options?: GetSelectorsOptions,