Product CRUD API

An in-memory version of the ShopEase product API. In the medium level the array is replaced by a database.

src/products/products.controller.ts

import { Body, Controller, Delete, Get, HttpCode, Param, ParseIntPipe, Patch, Post, Query } from '@nestjs/common';
import { ProductsService } from './products.service';
import { CreateProductDto } from './dto/create-product.dto';
import { UpdateProductDto } from './dto/update-product.dto';

@Controller('products')
export class ProductsController {
  constructor(private readonly productsService: ProductsService) {}

  @Get()
  findAll(@Query('category') category?: string) {
    return this.productsService.findAll(category);
  }

  @Get(':id')
  findOne(@Param('id', ParseIntPipe) id: number) {
    return this.productsService.findOne(id);
  }

  @Post()
  create(@Body() dto: CreateProductDto) {
    return this.productsService.create(dto);
  }

  @Patch(':id')
  update(@Param('id', ParseIntPipe) id: number, @Body() dto: UpdateProductDto) {
    return this.productsService.update(id, dto);
  }

  @Delete(':id')
  @HttpCode(204)
  remove(@Param('id', ParseIntPipe) id: number) {
    this.productsService.remove(id);
  }
}

src/products/products.service.ts

import { Injectable, NotFoundException } from '@nestjs/common';
import { CreateProductDto } from './dto/create-product.dto';
import { UpdateProductDto } from './dto/update-product.dto';

export interface Product { id: number; name: string; description?: string; price: number; stock: number; category: string; }

@Injectable()
export class ProductsService {
  private products: Product[] = [
    { id: 1, name: 'boAt Airdopes 141', price: 1299, stock: 120, category: 'audio' },
    { id: 2, name: 'Redmi Note 13', price: 17999, stock: 35, category: 'mobiles' },
  ];
  private nextId = 3;

  findAll(category?: string) {
    return category ? this.products.filter((p) => p.category === category) : this.products;
  }

  findOne(id: number) {
    const product = this.products.find((p) => p.id === id);
    if (!product) throw new NotFoundException(`Product ${id} not found`);
    return product;
  }

  create(dto: CreateProductDto) {
    const product = { id: this.nextId++, ...dto };
    this.products.push(product);
    return product;
  }

  update(id: number, dto: UpdateProductDto) {
    const product = this.findOne(id);
    Object.assign(product, dto);
    return product;
  }

  remove(id: number) {
    this.findOne(id);
    this.products = this.products.filter((p) => p.id !== id);
  }
}