NestJs Ecommerce Development — Part I

In this tutorial series we will use NestJs to develop a simple Ecommerce backend. The database used is MongoDB.

Start with NestJs cli to create a new app —

nest new nestjs-ecommerce

Add Mongoose —

npm install --save mongoose

Next add mongoose module in AppModule imports section —

MongooseModule.forRoot(‘mongodb://localhost/nestjs-ecommerce’

Our next step is to create Category module —

Create module using- 'nest g module category'
category
 — dtos
 — schemas
category.controller.ts
category.service.ts
category.module.ts

Category model will have unique slug. So using plugin mongoose-slug-generator. Category schemas folder has schema for Category —

import { Prop, Schema, SchemaFactory } from ‘@nestjs/mongoose’;
import { Document } from ‘mongoose’;
export type CategoryDocument = Category & Document;
@Schema()
export class Category {
@Prop({ required: true })
name: string;
@Prop({ slug: 'name', unique: true }) // The slug: 'name' will //create unique slugs on name property.
slug: string;
@Prop()
banner: string;
}
export const CategorySchema = SchemaFactory.createForClass(Category);

To activate plugin with mongoose feature module category we have to add the below lines in CategoryModule imports section.

MongooseModule.forFeatureAsync([{
name: Category.name,
useFactory: () => {
const schema = CategorySchema;
schema.plugin(require(‘mongoose-slug-generator’));
return schema;
},
}])

Next we need a data transfer object for carrying data between service and controller.

// We need class-validator to validate api
// npm i --save class-validator class-transformer
import { IsNotEmpty } from “class-validator”;
export class CategoryDto {
@IsNotEmpty()
name: string;
slug: string;
banner: string;
}

Next we will create category service —

import { Injectable } from ‘@nestjs/common’;
import { InjectModel } from ‘@nestjs/mongoose’;
import { Model } from ‘mongoose’;
import { Category, CategoryDocument } from ‘./schemas/category.schema’;
import { CategoryDto } from ‘./dtos/category-dto’;
@Injectable()
export class CategoryService {
constructor(@InjectModel(Category.name) private catModel: Model<CategoryDocument>) {}
async create(categoryDto: CategoryDto): Promise<Category> {
const createdCat = new this.catModel(categoryDto);
return createdCat.save();
}
async update(categoryDto: CategoryDto, id: string): Promise<Category> {
return this.catModel.findByIdAndUpdate(id, {…categoryDto}, {useFindAndModify: false}).exec();
}
async findAll(): Promise<Category[]> {
return this.catModel.find().exec();
}
async findOne(id: string): Promise<Category> {
return this.catModel.findById(id).exec();
}
async findOneBySlug(slug: string): Promise<Category> {
return this.catModel.findOne({slug}).exec();
}
async deleteOne(id: string): Promise<Category> {
return this.catModel.deleteOne({ _id: id}).exec();
}
}

And at last the controller

import { Body, Controller, Delete, Get, Param, Post, Put, ValidationPipe } from ‘@nestjs/common’;
import { Category } from ‘./schemas/category.schema’;
import { CategoryService } from ‘./category.service’;
import { CategoryDto } from ‘./dtos/category-dto’;
@Controller(‘category’)
export class CategoryController {
constructor(private readonly catService: CategoryService) {}
@Post()
// ValidationPipe() will help to validate input body using 'class-validator'
async create(@Body(new ValidationPipe()) categoryDto: CategoryDto) {
await this.catService.create(categoryDto);
}
@Get()
async findAll(): Promise<Category[]> {
return this.catService.findAll();
}
@Get(‘:id’)
findOne(@Param(‘id’) id: string) {
return this.catService.findOne(id);
}
@Get('categoryBySlug/:slug')
findOneBySlug(@Param('slug') slug: string) {
return this.catService.findOneBySlug(slug);
}
@Put(‘:id’)
update(@Param(‘id’) id: string, @Body() updateCatDto: CategoryDto) {
return this.catService.update(updateCatDto, id);
}
@Delete(‘:id’)
remove(@Param(‘id’) id: string) {
return this.catService.deleteOne(id);
}
}

So we now have /category API with POST, PUT, GET and DELETE with input validation and slugify.

Next we will create the Product module and add relationship between Category and Product.

Github link https://github.com/asif633/nestjs-ecommerce

Thank you.