feat: standardize pagination and response structure for API data services

packages/core-api/src/data-services/base-data.transformer.ts

@@ -1,5 +1,42 @@
 import type { BaseEntity } from './types';
 
+export interface NestJSPaginationMeta {
+  currentPage: number;
+  itemsPerPage: number;
+  totalItems: number;
+  totalPages: number;
+  itemCount?: number;
+  [key: string]: any;
+}
+
+export interface StandardPaginationMeta {
+  page: number;
+  limit: number;
+  total: number;
+  totalPages: number;
+}
+
+export interface PaginatedResponse<T> {
+  data: T[];
+  meta: StandardPaginationMeta;
+}
+
+export function defaultTransformPaginationMeta(meta: any): StandardPaginationMeta {
+  if (!meta) {
+    return { page: 1, limit: 10, total: 0, totalPages: 0 };
+  }
+  return {
+    page: meta.currentPage ?? meta.page ?? 1,
+    limit: meta.itemsPerPage ?? meta.limit ?? 10,
+    total: meta.totalItems ?? meta.total ?? 0,
+    totalPages: meta.totalPages ?? 0,
+  };
+}
+
+export interface SingleResponse<T> {
+  data: T;
+}
+
 // ─── Core Transformer Interface ─────────────────────────────────
 
 /**
@@ -81,6 +118,12 @@ export interface IDataTransformer<TEntity extends BaseEntity = BaseEntity, TDTO
    * If not provided, falls back to identity.
    */
   transformPayloadFilter?(filter: Record<string, any>): Record<string, any>;
+
+  /**
+   * Transform the pagination meta object from a `getMany()` call.
+   * If not provided, falls back to standardizing NestJS meta.
+   */
+  transformPaginationMeta?(meta: any): StandardPaginationMeta;
 }
 
 // ─── Abstract Base Transformer ──────────────────────────────────
@@ -232,4 +275,17 @@ export abstract class BaseDataTransformer<TEntity extends BaseEntity = BaseEntit
   transformPayloadFilter(filter: Record<string, any>): Record<string, any> {
     return filter;
   }
+
+  /**
+   * Transform the pagination meta object from a `getMany()` call.
+   *
+   * Override this if the API returns a completely different meta
+   * structure that the default NestJS parser cannot handle.
+   *
+   * @param meta - The raw meta object from the API response
+   * @returns The standardized pagination meta
+   */
+  transformPaginationMeta(meta: any): StandardPaginationMeta {
+    return defaultTransformPaginationMeta(meta);
+  }
 }

packages/core-api/src/data-services/base-remote.data-services.test.ts

@@ -10,7 +10,10 @@ import { BaseDataTransformer } from './base-data.transformer';
 function createMockHttpClient(): AxiosInstance {
   return {
     request: vi.fn().mockResolvedValue({
+      data: {
         data: [{ id: '1', name: 'Test' }],
+        meta: { currentPage: 1, itemsPerPage: 10, totalItems: 1, totalPages: 1 },
+      },
       status: 200,
     }),
     // Satisfy the AxiosInstance shape (unused properties)
@@ -224,14 +227,14 @@ describe('BaseRemoteDataServices (via CommonRemoteDataServices)', () => {
   describe('response shape', () => {
     it('returns { data, status } from the Axios response', async () => {
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValueOnce({
-        data: { id: '42', bookingCode: 'BK042', customerName: 'Alice' },
+        data: { data: { id: '42', bookingCode: 'BK042', customerName: 'Alice' } },
         status: 200,
       });
 
-      const result = await services.getOne<TestEntity>('42');
+      const result = await services.getOne('42');
 
       expect(result).toEqual({
-        data: { id: '42', bookingCode: 'BK042', customerName: 'Alice' },
+        data: { data: { id: '42', bookingCode: 'BK042', customerName: 'Alice' } },
         status: 200,
       });
     });
@@ -341,7 +344,7 @@ describe('BaseRemoteDataServices — Data Transformer Integration', () => {
     it('getOne() returns raw API response unchanged', async () => {
       const rawDTO = { id: '42', booking_code: 'BK042', customer_name: 'Alice' };
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValueOnce({
-        data: rawDTO,
+        data: { data: rawDTO },
         status: 200,
       });
 
@@ -350,7 +353,7 @@ describe('BaseRemoteDataServices — Data Transformer Integration', () => {
       });
 
       const result = await services.getOne('42');
-      expect(result.data).toEqual(rawDTO);
+      expect(result.data).toEqual({ data: rawDTO });
     });
 
     it('getMany() returns raw API response unchanged', async () => {
@@ -359,7 +362,10 @@ describe('BaseRemoteDataServices — Data Transformer Integration', () => {
         { id: '2', booking_code: 'BK002', customer_name: 'Bob' },
       ];
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValueOnce({
+        data: {
           data: rawDTOs,
+          meta: { currentPage: 2, itemsPerPage: 10, totalItems: 2, totalPages: 1 },
+        },
         status: 200,
       });
 
@@ -368,7 +374,10 @@ describe('BaseRemoteDataServices — Data Transformer Integration', () => {
       });
 
       const result = await services.getMany();
-      expect(result.data).toEqual(rawDTOs);
+      expect(result.data).toEqual({
+        data: rawDTOs,
+        meta: { page: 2, limit: 10, total: 2, totalPages: 1 },
+      });
     });
 
     it('create() sends entity data as-is without transformation', async () => {
@@ -400,46 +409,57 @@ describe('BaseRemoteDataServices — Data Transformer Integration', () => {
 
     it('getOne() transforms API DTO to domain entity', async () => {
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValueOnce({
-        data: { id: '42', booking_code: 'BK042', customer_name: 'Alice' },
+        data: { data: { id: '42', booking_code: 'BK042', customer_name: 'Alice' } },
         status: 200,
       });
 
       const result = await services.getOne('42');
 
       expect(result.data).toEqual({
+        data: {
           id: '42',
           bookingCode: 'BK042',
           customerName: 'Alice',
+        }
       });
       expect(result.status).toBe(200);
     });
 
     it('getMany() transforms each DTO in the array to entities', async () => {
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValueOnce({
+        data: {
           data: [
             { id: '1', booking_code: 'BK001', customer_name: 'Alice' },
             { id: '2', booking_code: 'BK002', customer_name: 'Bob' },
           ],
+          meta: { currentPage: 1, itemsPerPage: 15, totalItems: 2, totalPages: 1 }
+        },
         status: 200,
       });
 
       const result = await services.getMany();
 
-      expect(result.data).toEqual([
+      expect(result.data).toEqual({
+        data: [
           { id: '1', bookingCode: 'BK001', customerName: 'Alice' },
           { id: '2', bookingCode: 'BK002', customerName: 'Bob' },
-      ]);
+        ],
+        meta: { page: 1, limit: 15, total: 2, totalPages: 1 }
+      });
     });
 
     it('getMany() handles empty array response', async () => {
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValueOnce({
-        data: [],
+        data: { data: [], meta: {} },
         status: 200,
       });
 
       const result = await services.getMany();
 
-      expect(result.data).toEqual([]);
+      expect(result.data).toEqual({
+        data: [],
+        meta: { page: 1, limit: 10, total: 0, totalPages: 0 }
+      });
     });
 
     it('create() transforms entity payload to DTO before sending', async () => {
@@ -510,28 +530,36 @@ describe('BaseRemoteDataServices — Data Transformer Integration', () => {
 
     it('getOne() uses transformGetOneResponse hook (uppercases customer name)', async () => {
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValueOnce({
-        data: { id: '42', booking_code: 'BK042', customer_name: 'alice' },
+        data: { data: { id: '42', booking_code: 'BK042', customer_name: 'alice' } },
         status: 200,
       });
 
       const result = await services.getOne('42');
 
       expect(result.data).toEqual({
+        data: {
           id: '42',
           bookingCode: 'BK042',
           customerName: 'ALICE', // uppercased by custom hook
+        }
       });
     });
 
     it('getMany() uses transformGetManyResponse hook (prefixes booking code)', async () => {
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValueOnce({
+        data: {
           data: [{ id: '1', booking_code: 'BK001', customer_name: 'Alice' }],
+          meta: { currentPage: 1, itemsPerPage: 10, totalItems: 1, totalPages: 1 },
+        },
         status: 200,
       });
 
       const result = await services.getMany();
 
-      expect(result.data).toEqual([{ id: '1', bookingCode: 'LIST-BK001', customerName: 'Alice' }]);
+      expect(result.data).toEqual({
+        data: [{ id: '1', bookingCode: 'LIST-BK001', customerName: 'Alice' }],
+        meta: { page: 1, limit: 10, total: 1, totalPages: 1 }
+      });
     });
 
     it('create() uses transformCreatePayload hook (strips id)', async () => {
@@ -561,7 +589,7 @@ describe('BaseRemoteDataServices — Data Transformer Integration', () => {
 
   describe('with identity transformer (default passthrough)', () => {
     it('produces same results as no transformer', async () => {
-      const rawData = { id: '1', name: 'Test' };
+      const rawData = { data: { id: '1', name: 'Test' } };
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValue({
         data: rawData,
         status: 200,
@@ -592,7 +620,7 @@ describe('BaseRemoteDataServices — Data Transformer Integration', () => {
     it('transformGetOneResponse receives the raw DTO from API', async () => {
       const rawDTO = { id: '42', booking_code: 'BK042', customer_name: 'Alice' };
       (mockClient.request as ReturnType<typeof vi.fn>).mockResolvedValueOnce({
-        data: rawDTO,
+        data: { data: rawDTO },
         status: 200,
       });
 

packages/core-api/src/data-services/base-remote.data-services.ts

@@ -8,7 +8,12 @@ import type {
   DataServicesConfig,
   EntityId,
 } from './types';
-import type { IDataTransformer } from './base-data.transformer';
+import {
+  type IDataTransformer,
+  type PaginatedResponse,
+  type SingleResponse,
+  defaultTransformPaginationMeta,
+} from './base-data.transformer';
 import type { ApiResponse } from '../http-client/types';
 import { interpolateUrl } from './url-builder';
 import { DEFAULT_METHODS, DESCRIPTORS, makeDefaultURLs } from './constants';
@@ -167,19 +172,34 @@ export abstract class BaseRemoteDataServices<E extends BaseEntity = BaseEntity,
    * When a transformer is injected, the raw API response is passed
    * through `transformGetManyResponse()` before being returned.
    */
-  async getMany<T = E[]>(config?: AxiosRequestConfig): Promise<ApiResponse<T>> {
+  async getMany<T = PaginatedResponse<E>>(config?: AxiosRequestConfig): Promise<ApiResponse<T>> {
-    const finalConfig = config?.params && this.transformer?.transformPayloadFilter
+    const finalConfig =
+      config?.params && this.transformer?.transformPayloadFilter
         ? { ...config, params: this.transformer.transformPayloadFilter(config.params) }
         : config;
 
     const result = await this.execute<T>(DESCRIPTORS.getMany, { config: finalConfig });
+    const responseData = result.data as unknown as PaginatedResponse<TDTO> & { meta: any };
 
-    if (this.transformer && Array.isArray(result.data)) {
+    if (responseData?.data && Array.isArray(responseData.data)) {
+      if (this.transformer) {
         return {
           ...result,
+          data: {
+            ...responseData,
             data: this.transformer.transformGetManyResponse
-          ? this.transformer.transformGetManyResponse(result.data as unknown as TDTO[])
+              ? this.transformer.transformGetManyResponse(responseData.data)
-          : result.data.map((item: unknown) => this.transformer!.transformToEntity(item as TDTO)),
+              : responseData.data.map((item: TDTO) => this.transformer!.transformToEntity(item)),
+            meta: this.transformer?.transformPaginationMeta
+              ? this.transformer.transformPaginationMeta(responseData.meta)
+              : defaultTransformPaginationMeta(responseData.meta),
+          },
+        } as unknown as ApiResponse<T>;
+      }
+
+      return {
+        ...result,
+        data: responseData,
       } as unknown as ApiResponse<T>;
     }
 
@@ -192,18 +212,22 @@ export abstract class BaseRemoteDataServices<E extends BaseEntity = BaseEntity,
    * When a transformer is injected, the raw API response is passed
    * through `transformGetOneResponse()` before being returned.
    */
-  async getOne<T = E>(id: string, config?: AxiosRequestConfig): Promise<ApiResponse<T>> {
+  async getOne<T = SingleResponse<E>>(id: string, config?: AxiosRequestConfig): Promise<ApiResponse<T>> {
     const result = await this.execute<T>(DESCRIPTORS.getOne, {
       variableURL: { id },
       config,
     });
+    const responseData = result.data as unknown as SingleResponse<TDTO>;
 
-    if (this.transformer && result.data != null) {
+    if (this.transformer && responseData?.data != null) {
       return {
         ...result,
+        data: {
+          ...responseData,
           data: this.transformer.transformGetOneResponse
-          ? this.transformer.transformGetOneResponse(result.data as unknown as TDTO)
+            ? this.transformer.transformGetOneResponse(responseData.data)
-          : this.transformer.transformToEntity(result.data as unknown as TDTO),
+            : this.transformer.transformToEntity(responseData.data),
+        },
       } as unknown as ApiResponse<T>;
     }