[#94] Backend

https://project.mdnd-it.cc/work_packages/94

SerpentRace_Backend/src/Application/Contact/queries/GetContactByIdQueryHandler.ts

@@ -0,0 +1,16 @@
+import { IContactRepository } from '../../../Domain/IRepository/IContactRepository';
+import { GetContactByIdQuery } from './GetContactByIdQuery';
+import { DetailContactDto } from '../../DTOs/ContactDto';
+import { ContactMapper } from '../../DTOs/Mappers/ContactMapper';
+
+export class GetContactByIdQueryHandler {
+  constructor(private readonly contactRepo: IContactRepository) {}
+
+  async execute(query: GetContactByIdQuery): Promise<DetailContactDto | null> {
+    const contact = await this.contactRepo.findById(query.id);
+    if (!contact) {
+      return null;
+    }
+    return ContactMapper.toDetailDto(contact);
+  }
+}