feat: implement response interceptor

src/core/response/constants.ts

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+export const PAGINATION_RESPONSE = 'PAGINATION_RESPONSE';

src/core/response/domain/decorators/pagination.response.ts

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+import { SetMetadata } from '@nestjs/common';
+import { PAGINATION_RESPONSE } from '../../constants';
+
+/**
+ * This decorator will tell the response,
+ * that this request is pagination type
+ */
+export const Pagination = (isPagination = true) =>
+  SetMetadata(PAGINATION_RESPONSE, isPagination);

src/core/response/domain/exceptions/handled-exception.ts

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+import {
+  ExceptionFilter,
+  Catch,
+  ArgumentsHost,
+  HttpException,
+} from '@nestjs/common';
+import { Response } from 'express';
+
+@Catch(HttpException)
+export class HttpExceptionFilter implements ExceptionFilter {
+  catch(exception: HttpException, host: ArgumentsHost) {
+    const ctx = host.switchToHttp();
+    const response = ctx.getResponse<Response>();
+    const status = exception.getStatus();
+
+    response.status(status).json(exception.getResponse());
+  }
+}

src/core/response/domain/ok-response.interface.ts

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+export interface PaginationMeta {
+  currentPage: number;
+  itemCount: number;
+  itemsPerPage: number;
+  totalItems: number;
+  totalPages: number;
+}
+
+export interface SuccessResponse<T> {
+  data: T;
+  meta?: PaginationMeta;
+}
+
+export interface PaginationResponse<T> {
+  data: T[];
+  total: number;
+}

src/core/response/domain/response.interceptor.ts

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+import {
+  Injectable,
+  NestInterceptor,
+  ExecutionContext,
+  CallHandler,
+} from '@nestjs/common';
+import { Observable } from 'rxjs';
+import { map } from 'rxjs/operators';
+import { Request } from 'express';
+import { Reflector } from '@nestjs/core';
+import { PAGINATION_RESPONSE } from '../constants';
+import { createPaginationResponse } from './utils/pagination-meta.helper';
+
+@Injectable()
+export class TransformInterceptor implements NestInterceptor {
+  constructor(protected readonly reflector: Reflector) {}
+  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
+    const isPagination = this.reflector.getAllAndOverride<boolean>(
+      PAGINATION_RESPONSE,
+      [context.getHandler(), context.getClass()],
+    );
+
+    const request = context.switchToHttp().getRequest<Request>();
+    const start = request.params.page ?? 1;
+    const limit = request.params.limit ?? 10;
+
+    return next.handle().pipe(
+      map((data) => {
+        return isPagination
+          ? createPaginationResponse(data, +start, +limit)
+          : { data };
+      }),
+    );
+  }
+}

src/core/response/domain/utils/pagination-meta.helper.ts

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+import { PaginationMeta, PaginationResponse } from '../ok-response.interface';
+
+export function createPaginationMeta(
+  start: number,
+  limit: number,
+  dataCount: number,
+  total: number,
+): PaginationMeta {
+  return {
+    currentPage: start,
+    itemCount: dataCount,
+    itemsPerPage: limit,
+    totalItems: +total,
+    totalPages: Math.ceil(+total / limit),
+  };
+}
+
+export function createPaginationResponse<T>(
+  response: PaginationResponse<T>,
+  start: number,
+  limit: number,
+) {
+  const { data, total } = response;
+  const meta = createPaginationMeta(start, limit, data.length, total);
+  return {
+    data,
+    meta,
+  };
+}

src/core/response/index.ts

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+export * from './domain/response.interceptor';
+export * from './domain/exceptions/handled-exception';
+export * from './domain/decorators/pagination.response';
+export * from './constants';