added expenses resource

src/expenses/expense-data.service.ts

@@ -0,0 +1,34 @@
+import { Injectable } from '@nestjs/common';
+import { DataSource, Repository } from 'typeorm';
+import { Expense } from './entities/expense.entity';
+import { UpdateExpenseDto } from './dto/update-expense.dto';
+import { CreateExpenseDto } from './dto/create-expense.dto';
+
+@Injectable()
+export class ExpenseDataService {
+  private expenses: Repository<Expense>;
+
+  public constructor(private dataSource: DataSource) {
+    this.expenses = this.dataSource.getRepository(Expense);
+  }
+
+  public async getAll(): Promise<Expense[]> {
+    return await this.expenses.find();
+  }
+
+  public async getById(id: string): Promise<Expense | null> {
+    return await this.expenses.findOneBy({ id });
+  }
+
+  public async create(expense: CreateExpenseDto): Promise<Expense> {
+    return await this.expenses.save(expense);
+  }
+
+  public async update(expense: UpdateExpenseDto): Promise<Expense> {
+    return await this.expenses.save(expense);
+  }
+
+  public async delete(id: string): Promise<void> {
+    await this.expenses.delete({ id });
+  }
+}