feat(nestjs): migrate to NestJS

packages/server/src/modules/Import/ImportFilePreview.ts

@@ -0,0 +1,40 @@
+import { ImportFilePreviewPOJO } from './interfaces';
+import { ImportFileProcess } from './ImportFileProcess';
+import { ImportAls } from './ImportALS';
+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class ImportFilePreview {
+  constructor(
+    private readonly importFile: ImportFileProcess,
+    private readonly importAls: ImportAls,
+  ) {}
+
+  /**
+   * Preview the imported file results before commiting the transactions.
+   * @param {string} importId -
+   * @returns {Promise<ImportFilePreviewPOJO>}
+   */
+  public async preview(importId: string): Promise<ImportFilePreviewPOJO> {
+    return this.importAls.runPreview<Promise<ImportFilePreviewPOJO>>(() =>
+      this.previewAlsRun(importId),
+    );
+  }
+
+  /**
+   * Preview the imported file results before commiting the transactions.
+   * @param {number} importId
+   * @returns {Promise<ImportFilePreviewPOJO>}
+   */
+  public async previewAlsRun(importId: string): Promise<ImportFilePreviewPOJO> {
+    const knex = this.tenancy.knex(tenantId);
+    const trx = await knex.transaction({ isolationLevel: 'read uncommitted' });
+
+    const meta = await this.importFile.import(importId, trx);
+
+    // Rollback the successed transaction.
+    await trx.rollback();
+
+    return meta;
+  }
+}