REST APIs

The Goal

We will discuss how to create a REST API in Nest.

We will talk about modules, controllers, and services.

Create a REST API for our features in Nest

The Commands

Generate a REST resource for each feature.

npx nx g @nx/nest:resource --name=challenges --crud=true --project=challenges-api --type=rest 
npx nx g @nx/nest:resource --name=flashcards --crud=true --project=flashcards-api --type=rest
npx nx g @nx/nest:resource --name=notes --crud=true --project=notes-api --type=rest
npx nx g @nx/nest:resource --name=users --crud=true --project=users-api --type=rest

npx nx g @nx/nest:resource --name=features --crud=true --project=features-api --type=rest

The Code

Module

import { Module } from '@nestjs/common';
import { ChallengesService } from './challenges.service';
import { ChallengesController } from './challenges.controller';

@Module({
  controllers: [ChallengesController],
  providers: [ChallengesService],
})
export class ChallengesModule {}

Controller

import {
  Body,
  Controller,
  Delete,
  Get,
  Param,
  Patch,
  Post,
} from '@nestjs/common';
import { Challenge } from '../database/entities/challenge.entity';
import { ChallengesService } from './challenges.service';

@Controller('challenges')
export class ChallengesController {
  constructor(private readonly challengesService: ChallengesService) {}

  @Post()
  create(@Body() challenge: Challenge): Promise<Challenge> {
    return this.challengesService.create(challenge);
  }

  @Get()
  findAll(): Promise<Challenge[]> {
    return this.challengesService.findAll();
  }

  @Get(':id')
  findOne(@Param('id') id: string): Promise<Challenge> {
    return this.challengesService.findOne(id);
  }

  @Patch(':id')
  update(@Param('id') id: string, @Body() challenge: Challenge) {
    return this.challengesService.update(challenge);
  }

  @Delete(':id')
  remove(@Param('id') id: string) {
    return this.challengesService.remove(id);
  }
}

Service

import { Injectable, Inject, NotFoundException } from '@nestjs/common';
import { Repository, DeleteResult } from 'typeorm';
import { Challenge } from '../database/entities/challenge.entity';

@Injectable()
export class ChallengesService {
  constructor(
    @Inject('CHALLENGE_REPOSITORY')
    private challengesRepository: Repository<Challenge>,
  ) {}

  async findAll(): Promise<Challenge[]> {
    return await this.challengesRepository.find();
  }

  async findOne(id: string): Promise<Challenge | undefined> {
    return await this.challengesRepository.findOneBy({ id });
  }

  async get(id: string): Promise<Challenge> {
    const challenge = await this.challengesRepository.findOneBy({ id });
    if (!challenge) throw new NotFoundException();
    return challenge;
  }

  async create(challenge: Challenge): Promise<Challenge> {
    return await this.challengesRepository.save(challenge);
  }

  async update(challenge: Challenge): Promise<Challenge> {
    return await this.challengesRepository.save(challenge);
  }

  async remove(id: string): Promise<DeleteResult> {
    const challenge = await this.challengesRepository.findOneBy({ id });
    if (!challenge) throw new NotFoundException();
    return await this.challengesRepository.delete(id);
  }
}