diff --git a/src/lib/services/entities-map.service.ts b/src/lib/services/entities-map.service.ts
index bec6c00..ffd7fc5 100644
--- a/src/lib/services/entities-map.service.ts
+++ b/src/lib/services/entities-map.service.ts
@@ -1,9 +1,10 @@
 import { Injectable } from '@angular/core';
-import { BehaviorSubject, Observable, Subject, switchMap } from 'rxjs';
+import { BehaviorSubject, Observable, Subject } from 'rxjs';
 import { filter, map, startWith } from 'rxjs/operators';
 import { Entity } from '../listing';
-import { RequiredParam, shareLast, Validate } from '../utils';
+import { List, RequiredParam, shareLast, Validate } from '../utils';
 import { Id } from '../listing/models/trackable';
+import { isArray } from '../permissions';
 
 @Injectable({ providedIn: 'root' })
 export abstract class EntitiesMapService<Interface, Class extends Entity<Interface, PrimaryKey>, PrimaryKey extends Id = Class['id']> {
@@ -18,20 +19,32 @@ export abstract class EntitiesMapService<Interface, Class extends Entity<Interfa
         return this._map.size === 0;
     }
 
-    delete(keys: Id[]): void {
-        keys.forEach(key => this._map.delete(key));
+    delete(keys: List<Id>): void;
+    delete(key: Id, entity: PrimaryKey | Class): void;
+    delete(keys: List<Id> | Id, entity?: PrimaryKey | Class): void {
+        if (isArray(keys)) {
+            return keys.forEach(key => this._map.delete(key));
+        }
+
+        if (entity) {
+            const entityId = typeof entity === 'string' || typeof entity === 'number' ? entity : entity.id;
+            const entities = this.get(keys).filter(entity => entity.id !== entityId);
+            this.set(keys, entities);
+        }
+
+        console.error('entityId is null when deleting from EntitiesMapService');
     }
 
     get$(key: Id) {
-        if (!this._map.has(key)) {
+        if (!this.has(key)) {
             this._map.set(key, new BehaviorSubject<Class[]>([]));
         }
 
         return this._getBehaviourSubject(key).asObservable();
     }
 
-    has(parentId: Id) {
-        return this._map.has(parentId);
+    has(key: Id) {
+        return this._map.has(key);
     }
 
     get(key: Id): Class[];
@@ -55,7 +68,7 @@ export abstract class EntitiesMapService<Interface, Class extends Entity<Interfa
 
         // Keep old object references for unchanged entities
         const newEntities: Class[] = entities.map(newEntity => {
-            const oldEntity: Class | undefined = this.get(key, newEntity.id);
+            const oldEntity = this.get(key, newEntity.id);
 
             if (oldEntity && newEntity.isEqual(oldEntity)) {
                 return oldEntity;
@@ -82,9 +95,13 @@ export abstract class EntitiesMapService<Interface, Class extends Entity<Interfa
         }
     }
 
-    replace(entities: Class[]) {
-        /** Return true if entities were replaced or false if not **/
-        const key = this._pluckPrimaryKey(entities[0]);
+    add(key: string, entity: Class) {
+        const entities = this.get(key);
+        this.set(key, [...entities, entity]);
+    }
+
+    /** Return true if entities were replaced or false if not */
+    replace(key: string, entities: Class[]) {
         const entityIds = entities.map(entity => entity.id);
         const existingEntities = this.get(key).filter(entity => entityIds.includes(entity.id));
         const newEntities = entities.filter(entity => {
@@ -93,7 +110,8 @@ export abstract class EntitiesMapService<Interface, Class extends Entity<Interfa
         });
 
         if (newEntities.length) {
-            const all = this.get(key).filter(e => !newEntities.map(entity => entity.id).includes(e.id));
+            const newEntitiesIds = newEntities.map(entity => entity.id);
+            const all = this.get(key).filter(e => !newEntitiesIds.includes(e.id));
             this.set(key, [...all, ...newEntities]);
             return true;
         }
@@ -112,6 +130,7 @@ export abstract class EntitiesMapService<Interface, Class extends Entity<Interfa
 
     @Validate()
     watchChanged$(@RequiredParam() key: Id): Observable<boolean> {
+        // TODO: This is wrong, entityChanged emits only one entity at a time
         return this.#entityChanged$.pipe(
             startWith(this.get(key)),
             map(entities => entities as Class[]),
@@ -123,12 +142,6 @@ export abstract class EntitiesMapService<Interface, Class extends Entity<Interfa
         return this.#entityDeleted$.pipe(filter(entity => entity.id === entityId));
     }
 
-    private _pluckPrimaryKey(entity: Class): Id {
-        // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-        // @ts-ignore
-        return entity[this._primaryKey] as Id;
-    }
-
     private _getBehaviourSubject(key: Id): BehaviorSubject<Class[]> {
         // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
         return this._map.get(key)!;