following Course

Root Module is app.module

to generate new files use cli:

• nest generate ... [name]
  • controller
  • module

useful decorators for controller: decorators are prededefined functions.

@Get @Post @Param @Query @Controller

When dealing with data its handy to use DTO's to define what data is send to controller.

Nest Docs

yarn add class-validator class-transformer

• use decorator from class Validator inside DTO to ensure validation
• add Validation Pipe to Controller @UsePipes(new ValidationPipe())

@Param('id', ParseIntPipe)

Providers are injected. Nestjs uses Dependency Injection.

Take care of the Business Logic. Seperation of Concerns. nest generate service /users/services/users or nest g s /users/services/users

every provider has @Injectable() Decorator. This means Nest is able to do dependency injection

Run before Controller. Has access to Request and Response.

nest generate middleware

special way to register. Add as Consumer `` export class UsersModule implements NestModule { configure(consumer: MiddlewareConsumer) { consumer.apply(ExampleMiddleware).forRoutes('users'); } }

``

two usecases Transformation:

• Transform properties (Strings-> Int, ...)

Validation:

• check req body

useful to guarantee certain types.

create new Pipe with cli tool

validateCreateUser

This pipe is added to the controller function

createUser(@Body(ValidateCreateUserPipe) userData: CreateUserDto)

idea: maybe useful for specific DateTime Format etc.

a class with the responsibility to decide if the incoming req can be handled by the controller.

authentication, authorisation(roles, etc)

nest g guard /users/guards/Auth

add the annotation to the controller or function @UseGuards(AuthGuard)