C. Membuat Base Response

Untuk membuat penulisan response menjadi sederhana saat return dalam service, kita akan membuat class Base Response pada folder utils seperti gambar di bawah.

utils/response/base.response.ts

import { ResponseSuccess, ResponsePagination } from "src/interface/response";

class BaseResponse {
  _success(message: string, data?: any): ResponseSuccess {
    return {
      status: "Success",
      message: message,
      data: data || {},
    };
  }

  _pagination(
    message: string,
    data: any,
    totalData: number,
    page: number,
    pageSize: number
  ): ResponsePagination {
    return {
      status: "Success",
      message: message,
      data: data,
      pagination: {
        total: totalData,
        page: page,
        pageSize: pageSize,
      },
    };
  }
}

export default BaseResponse;

Kemudian class tersebut kita extends pada book.service.ts

book.service.ts

import {
  HttpException,
  HttpStatus,
  Injectable,
  NotFoundException,
} from '@nestjs/common';
import { ResponsePagination, ResponseSuccess } from 'src/interface/response';
import { CreateBookDto, FindBookDto, UpdateBookDto } from './book.dto';
import { InjectRepository } from '@nestjs/typeorm';
import { Book } from './book.entity';
import { Between, Like, Repository } from 'typeorm';
import BaseResponse from 'src/utils/response/base.response'; //import class Base Response

@Injectable()
export class BookService extends BaseResponse { //extend class BaseResponse
  constructor(
    @InjectRepository(Book) private readonly bookRepository: Repository<Book>,
  ) {
    super(); // karena BookService menjadi sub class dari BaseResponse maka harus diberkan super()
  }

 ...

}

Setelah kita extends BaseResponse, selanjutkan kita impelementasikan pada return setiap method service di book.service.ts

book.service.ts

async getAllBooks(query: FindBookDto): Promise<ResponsePagination> {
    const { page, pageSize, limit, title, author, from_year, to_year } = query;

    console.log('q', query);
    const total = await this.bookRepository.count();

    const filter: {
      [key: string]: any;
    } = {};

    if (title) {
      filter.title = Like(`%${title}%`);
    }
    if (author) {
      filter.author = Like(`%${author}%`);
    }

    if (from_year && to_year) {
      filter.year = Between(from_year, to_year);
    }

    if (from_year && !!to_year === false) {
      filter.year = Between(from_year, from_year);
    }

    const result = await this.bookRepository.find({
      where: filter,

      skip: limit,
      take: pageSize,
    });

    return this._pagination('OK', result, total, page, pageSize); // implementasi method _pagination disini
  }

  async createBook(createBookDto: CreateBookDto): Promise<ResponseSuccess> {
    const { title, author, year } = createBookDto;

    try {
      await this.bookRepository.save({
        title: title,
        author: author,
        year: year,
      });
      return this._success('OK'); // implementasi method _success disini
    } catch (err) {
      throw new HttpException('Ada Kesalahan', HttpStatus.BAD_REQUEST);
    }
  }

Pengujian pada Postman create

Pengujian pada Postman get all dengan filter

Selanjutkan silahkan implementasikan pada method-method lain pada book.service.ts