NestJS code explainers

typescript

import { NestFactory } from '@nestjs/core';
import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
import { ValidationPipe } from '@nestjs/common';
import { ApiProperty } from '@nestjs/swagger';

Wiring validation and Swagger docs in NestJS

validation openapi decorators

Intermediate 8 steps

typescript

import { Injectable, NestInterceptor, ExecutionContext, CallHandler } from '@nestjs/common';
import { Observable, catchError, concatMap, finalize } from 'rxjs';
import { DataSource, QueryRunner } from 'typeorm';

Wrapping requests in a transaction with NestJS

interceptors transactions rxjs

Advanced 7 steps

typescript

import {
  CanActivate,
  ExecutionContext,
  Injectable,

Role-based access with a NestJS guard

authorization guards decorators

Intermediate 6 steps

typescript

import { Exclude, Expose, Transform, Type } from 'class-transformer';
 
export class AddressEntity {
  street: string;

Shaping API responses with class-transformer in NestJS

serialization decorators dto

Intermediate 10 steps

typescript

import { Module } from '@nestjs/common';
import { ConfigModule, ConfigService } from '@nestjs/config';
import { createClient, RedisClientType } from 'redis';

Provide a Redis client with a NestJS factory

dependency-injection async-factory redis

Intermediate 6 steps

typescript

import { Controller } from '@nestjs/common';
import {
  MessagePattern,
  Payload,

Manual RabbitMQ acks in a NestJS controller

microservices message-queue acknowledgement

Intermediate 8 steps

typescript

import { Injectable, NotFoundException, ConflictException } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository, DeepPartial } from 'typeorm';
import { User } from './entities/user.entity';

Building a CRUD service in NestJS

crud dependency-injection repository-pattern

Intermediate 7 steps

typescript

import { Controller, Get, Param, Query, Redirect, NotFoundException } from '@nestjs/common';
import { LinksService } from './links.service';
 
@Controller('links')

Handling HTTP redirects in NestJS

redirects routing decorators

Intermediate 7 steps

typescript

import {
  CanActivate,
  ExecutionContext,
  Injectable,

How guards chain auth in NestJS

guards authentication authorization

Intermediate 8 steps

typescript

import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';
import { BullModule } from '@nestjs/bullmq';

How a NestJS feature module wires up

dependency-injection modularity orm

Intermediate 7 steps

typescript

import {
  Controller,
  Get,
  Query,

Validating paginated queries in NestJS

pagination validation pipes

Intermediate 7 steps

typescript

import { AsyncLocalStorage } from 'node:async_hooks';
import { randomUUID } from 'node:crypto';
import { Injectable, NestMiddleware } from '@nestjs/common';
import { Request, Response, NextFunction } from 'express';

Request correlation IDs in NestJS with AsyncLocalStorage

async-local-storage middleware logging

Advanced 8 steps

typescript

import {
  Controller,
  Post,
  UploadedFile,

Handling avatar uploads in NestJS

file-upload validation interceptors

Intermediate 7 steps

typescript

import { Injectable, UnauthorizedException } from '@nestjs/common';
import { PassportStrategy } from '@nestjs/passport';
import { ExtractJwt, Strategy } from 'passport-jwt';
import { ConfigService } from '@nestjs/config';

How a JWT strategy authenticates in NestJS

authentication jwt passport

Intermediate 7 steps

typescript

import { CanActivate, ExecutionContext, Injectable, UnauthorizedException } from '@nestjs/common';
import { GqlExecutionContext } from '@nestjs/graphql';
import { Reflector } from '@nestjs/core';
import { JwtService } from '@nestjs/jwt';

How a GraphQL auth guard works in NestJS

authentication authorization jwt

Intermediate 7 steps

typescript

import { Injectable, Logger, OnApplicationShutdown } from '@nestjs/common';
import { InjectRedis } from '@nestjs-modules/ioredis';
import Redis from 'ioredis';
import { DataSource } from 'typeorm';

Graceful shutdown hooks in NestJS

graceful-shutdown lifecycle-hooks dependency-injection

Intermediate 7 steps

typescript

import { Injectable, OnModuleInit, Logger } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { Cron, CronExpression } from '@nestjs/schedule';

A self-refreshing feature flags provider in NestJS

caching scheduled-tasks dependency-injection

Intermediate 8 steps

typescript

import { Test, TestingModule } from '@nestjs/testing';
import { getRepositoryToken } from '@nestjs/typeorm';
import { Repository } from 'typeorm';

Unit testing a NestJS service with mocked providers

dependency injection mocking unit testing

Intermediate 7 steps