add server to monorepo.

packages/server/src/services/UnitOfWork/index.ts

@@ -0,0 +1,56 @@
+import { Service, Inject } from 'typedi';
+import TenancyService from '@/services/Tenancy/TenancyService';
+
+/**
+ * Enumeration that represents transaction isolation levels for use with the {@link Transactional} annotation
+ */
+export enum IsolationLevel {
+  /**
+   * A constant indicating that dirty reads, non-repeatable reads and phantom reads can occur.
+   */
+  READ_UNCOMMITTED = 'read uncommitted',
+  /**
+   * A constant indicating that dirty reads are prevented; non-repeatable reads and phantom reads can occur.
+   */
+  READ_COMMITTED = 'read committed',
+  /**
+   * A constant indicating that dirty reads and non-repeatable reads are prevented; phantom reads can occur.
+   */
+  REPEATABLE_READ = 'repeatable read',
+  /**
+   * A constant indicating that dirty reads, non-repeatable reads and phantom reads are prevented.
+   */
+  SERIALIZABLE = 'serializable',
+}
+
+@Service()
+export default class UnitOfWork {
+  @Inject()
+  tenancy: TenancyService;
+
+  /**
+   *
+   * @param {number} tenantId
+   * @param {} work
+   * @param {IsolationLevel} isolationLevel
+   * @returns {}
+   */
+  public withTransaction = async (
+    tenantId: number,
+    work,
+    isolationLevel: IsolationLevel = IsolationLevel.READ_UNCOMMITTED
+  ) => {
+    const knex = this.tenancy.knex(tenantId);
+    const trx = await knex.transaction({ isolationLevel });
+
+    try {
+      const result = await work(trx);
+      trx.commit();
+
+      return result;
+    } catch (error) {
+      trx.rollback();
+      throw error;
+    }
+  };
+}