NestJS Course Built for AI-Paired Learning

This chapter focuses on What NestJS is and the problems it solves, Opinionated architecture and its benefits, Installing the Nest CLI and the practice needed to use these concepts confidently in real projects.

• What NestJS is and the problems it solves
• Opinionated architecture and its benefits
• Installing the Nest CLI
• Generating a project
• The project structure explained
• The bootstrap file and application factory
• Express and Fastify adapters
• TypeScript configuration for Nest
• Decorators and metadata reflection
• The CLI generate commands
• Controllers and route decorators
• Handling GET, POST, PUT, PATCH, DELETE
• Route parameters and query parameters
• Request body binding
• Response status and headers
• Custom response objects
• Redirects and file responses
• Async handlers and promises
• Sub-domain and versioned routing
• Global prefixes
• Hot reload in development
• Debugging a Nest application

This chapter focuses on The module system, The root module, Feature modules and the practice needed to use these concepts confidently in real projects.

• The module system
• The root module
• Feature modules
• imports, controllers, providers and exports
• Shared modules
• Global modules and when to use them
• Dynamic modules
• The forRoot and forFeature convention
• Async module configuration
• Providers and the Injectable decorator
• Constructor injection
• Custom providers: useValue
• Custom providers: useClass
• Custom providers: useFactory
• Injection tokens and symbols
• Optional dependencies
• Provider scopes: default, request, transient
• Request-scoped provider costs
• Circular dependencies and forwardRef
• The module reference API
• Lazy loading modules
• Structuring a large application

This chapter focuses on The execution order of pipeline elements, Middleware in Nest, Applying middleware to routes and the practice needed to use these concepts confidently in real projects.

• The execution order of pipeline elements
• Middleware in Nest
• Applying middleware to routes
• Functional middleware
• Guards and their purpose
• The CanActivate interface
• The execution context
• Role-based guards
• Guards with metadata and the Reflector
• Interceptors and their capabilities
• Transforming responses
• Logging and timing interceptors
• Caching interceptors
• Timeout interceptors
• Pipes and their two uses
• Built-in validation pipe
• Transformation pipes
• Custom pipes
• Exception filters
• Built-in HTTP exceptions
• Custom exception classes
• Global filters, guards, pipes and interceptors

This chapter focuses on Data transfer objects and their role, class-validator decorators, Nested object validation and the practice needed to use these concepts confidently in real projects.

• Data transfer objects and their role
• class-validator decorators
• Nested object validation
• Array validation
• Conditional validation
• Custom validators
• Async validators
• class-transformer basics
• Transforming incoming payloads
• Whitelisting and forbidding unknown properties
• Implicit type conversion
• Mapped types: PartialType and PickType
• OmitType and IntersectionType
• Serialisation with the ClassSerializerInterceptor
• Excluding sensitive fields
• Exposing computed fields
• Groups for different audiences
• Response DTOs
• Validation error formatting
• Localised messages
• Testing DTO validation
• Keeping DTOs and entities separate

This chapter focuses on Choosing an ORM for Nest, TypeORM integration, Prisma integration and the practice needed to use these concepts confidently in real projects.

• Choosing an ORM for Nest
• TypeORM integration
• Prisma integration
• Mongoose integration
• Configuring the database module asynchronously
• Entities and schemas
• Repositories and injection
• Custom repository methods
• One-to-one, one-to-many and many-to-many
• Eager and lazy relations
• Query builders
• Raw queries when needed
• Migrations and schema versioning
• Seeding data
• Transactions in services
• Unit of work patterns
• Soft deletes and timestamps
• Pagination helpers
• Indexing and query tuning
• Multiple database connections
• Testing repositories
• Handling database errors cleanly

This chapter focuses on Authentication approaches in Nest, The Passport integration, Local strategy for username and password and the practice needed to use these concepts confidently in real projects.

• Authentication approaches in Nest
• The Passport integration
• Local strategy for username and password
• Password hashing service
• JWT strategy and configuration
• Signing and verifying tokens
• Refresh token rotation
• Auth guards and public routes
• Custom decorators for the current user
• Role decorators and the Reflector
• Policy-based authorisation with CASL
• Resource ownership checks
• API key authentication
• OAuth providers
• Session-based auth in Nest
• Helmet and CORS setup
• Rate limiting with the throttler module
• CSRF considerations
• Secrets and configuration security
• Audit logging
• Security testing
• A hardening checklist

This chapter focuses on Custom parameter decorators, Custom method decorators, Composing decorators and the practice needed to use these concepts confidently in real projects.

• Custom parameter decorators
• Custom method decorators
• Composing decorators
• The Reflector and metadata patterns
• Lifecycle hooks
• Application shutdown hooks
• Configuration module and namespaces
• Validating configuration at startup
• Caching module and stores
• Task scheduling with cron
• Queues with BullMQ
• Job processors and retries
• Event emitter module
• Domain events and handlers
• The CQRS module
• Commands, queries and sagas
• File upload handling
• Streaming files
• Server-sent events
• WebSocket gateways
• Rooms, namespaces and broadcasts
• Health checks with Terminus

This chapter focuses on Documenting REST with Swagger, API decorators and schema generation, Examples and response models and the practice needed to use these concepts confidently in real projects.

• Documenting REST with Swagger
• API decorators and schema generation
• Examples and response models
• Authentication in Swagger UI
• Versioning strategies
• GraphQL module setup
• Code-first against schema-first
• Object types and resolvers
• Queries, mutations and subscriptions
• DataLoader and the N+1 problem
• GraphQL error handling
• Microservice transports overview
• TCP and Redis transports
• Message patterns and event patterns
• Request-response against event-based
• Kafka and RabbitMQ integration
• gRPC services in Nest
• Hybrid applications
• Service discovery considerations
• Distributed transactions and sagas
• Idempotent message handling
• Choosing the right style for a problem

This chapter focuses on The Nest testing module, Unit testing services with mocks, Mocking repositories and the practice needed to use these concepts confidently in real projects.

• The Nest testing module
• Unit testing services with mocks
• Mocking repositories
• Testing controllers
• Testing guards and interceptors
• Testing pipes and filters
• Overriding providers in tests
• End-to-end tests with supertest
• Test database strategies
• Test containers
• Seeding and cleaning between tests
• Testing authentication flows
• Testing queues and scheduled jobs
• Testing WebSocket gateways
• Coverage configuration
• Fast test suites in CI
• Linting and formatting
• Strict TypeScript settings
• Code review standards
• Refactoring with confidence
• Documenting modules
• Maintaining a large Nest codebase

This chapter focuses on Profiling a Nest application, Reducing startup time, Compression and payload size and the practice needed to use these concepts confidently in real projects.

• Profiling a Nest application
• Reducing startup time
• Compression and payload size
• Caching strategy across layers
• Database connection tuning
• Fastify adapter for throughput
• Clustering and process management
• Horizontal scaling and statelessness
• Graceful shutdown
• Logging in production
• Metrics and tracing
• Error tracking integration
• Environment configuration
• Building for production
• Dockerising a Nest service
• Multi-stage Docker builds
• CI/CD pipeline setup
• Database migrations on deploy
• Project: designing modules and contracts
• Project: implementing features end to end
• Project: testing and hardening
• Project: deployment and review