Slides from the NestJS MasterClass. We learned how to build JavaScript server-side applications with NestJS - A progressive NodeJS framework built with TypeScript. You can find the code on GitHub: https://github.com/nirkaufman/task-manager

1. MasterClass
Enter NestJS
Nir Kaufman | 2019

2. Nir Kaufman
@nirkaufman
Principal developer & consultant @ 500Tech
Google Developer Expert in Web Technologies

3. https://500tech.com/

4. meetup.com/reactNYC

5. Enter NestJS
The framework we where waiting for

6. Kamil Myśliwiec
@kammysliwiec

7. The building blocks

8. Modules
Package of related classes

9. Modules
Application Module

10. Modules
Application Module
Feature Module Feature Module Feature Module

11. Modules
Application Module
Feature Module Feature Module Feature Module
Shared Module

12. Modules
Blog
Posts Users Media
Utils

13. Modules
Root
Feature Feature
Shared

14. Controllers
Handling requests & responses

15. Controllers
Controller
Controller
Controller
HTTP Request

16. Providers
Plain Injectable classes

17. Providers
Controller
Controller
Controller
Provider
Provider
Provider

18. The structure
Clear separation of concerns

19. Layers architecture style
Providers
Controllers
Data

20. Wiring the database

21. Let’s do it the OOP style
Object-relational mapping

22. EntitiesEntities
Onion architecture style
Entities
Services
Controllers

23. Additional API

24. ControllerClient
Determine whether a given request will be handled by the controller
Guards
Guard

25. @Injectable()
export class AuthGuard implements CanActivate {
canActivate(context: ExecutionContext): boolean {
const token = context.switchToHttp().getRequest().headers.token;
return validateToken(token);
}
}
Auth Guard

26. @Injectable()
export class AuthGuard implements CanActivate {
canActivate(context: ExecutionContext): boolean {
const token = context.switchToHttp().getRequest().headers.token;
return validateToken(token);
}
}
Auth Guard

27. @Injectable()
export class AuthGuard implements CanActivate {
canActivate(context: ExecutionContext): boolean {
const token = context.switchToHttp().getRequest().headers.token;
return validateToken(token);
}
}
Auth Guard

28. ControllerClient
Implements the generic ExceptionFilter<T> interface
Exception filters
Guard
Filter
Filter

29. @Catch(ForbiddenException)
export class AuthFilter implements ExceptionFilter {
catch(exception: ForbiddenException, host: ArgumentsHost) {
const ctx = host.switchToHttp();
const response = ctx.getResponse();
const request = ctx.getRequest();
const status = exception.getStatus();
response.status(status).json({
statusCode: status,
timestamp: new Date().toISOString(),
path: request.url,
message: 'Protected method'
Auth Filter

30. @Catch(ForbiddenException)
export class AuthFilter implements ExceptionFilter {
catch(exception: ForbiddenException, host: ArgumentsHost) {
const ctx = host.switchToHttp();
const response = ctx.getResponse();
const request = ctx.getRequest();
const status = exception.getStatus();
response.status(status).json({
statusCode: status,
timestamp: new Date().toISOString(),
path: request.url,
message: 'Protected method'
Auth Filter

31. @Catch(ForbiddenException)
export class AuthFilter implements ExceptionFilter {
catch(exception: ForbiddenException, host: ArgumentsHost) {
const ctx = host.switchToHttp();
const response = ctx.getResponse();
const request = ctx.getRequest();
const status = exception.getStatus();
response.status(status).json({
statusCode: status,
timestamp: new Date().toISOString(),
path: request.url,
message: 'Protected method'
Auth Filter

32. @Catch(ForbiddenException)
export class AuthFilter implements ExceptionFilter {
catch(exception: ForbiddenException, host: ArgumentsHost) {
const ctx = host.switchToHttp();
const response = ctx.getResponse();
const request = ctx.getRequest();
const status = exception.getStatus();
response.status(status).json({
statusCode: status,
timestamp: new Date().toISOString(),
path: request.url,
message: 'Protected method'
Auth Filter

33. @Catch(ForbiddenException)
export class AuthFilter implements ExceptionFilter {
catch(exception: ForbiddenException, host: ArgumentsHost) {
const ctx = host.switchToHttp();
const response = ctx.getResponse();
const request = ctx.getRequest();
const status = exception.getStatus();
response.status(status).json({
statusCode: status,
timestamp: new Date().toISOString(),
path: request.url,
message: 'Protected method'
Auth Filter

34. ControllerClient
Transform input into desired output. validate input data
Pipes
Guard
Filter
Filter
Pipe
Pipe

35. @Injectable()
export class ValidatePipe implements PipeTransform {
transform(value: any, metadata: ArgumentMetadata) {
return value;
}
}
Basic Pipe

36. @Injectable()
export class ValidatePipe implements PipeTransform {
transform(value: any, metadata: ArgumentMetadata) {
return value;
}
}
Basic Pipe

37. @Injectable()
export class ValidatePipe implements PipeTransform {
transform(value: any, metadata: ArgumentMetadata) {
return value;
}
}
Basic Pipe

38. ControllerClient
bind extra logic before / after method execution
Interceptors
Guard
Filter
Filter
Pipe
Pipe
Interceptor
Interceptor

39. @Injectable()
export class LogInterceptor implements NestInterceptor {
intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
const requestInfo = {
time: new Date().toLocaleTimeString(),
controller: context.getClass().name,
method: context.getHandler().name
};
console.log(requestInfo);
return next.handle();
}
}
Log Interceptors

40. @Injectable()
export class LogInterceptor implements NestInterceptor {
intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
const requestInfo = {
time: new Date().toLocaleTimeString(),
controller: context.getClass().name,
method: context.getHandler().name
};
console.log(requestInfo);
return next.handle();
}
}
Log Interceptors

41. @Injectable()
export class LogInterceptor implements NestInterceptor {
intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
const requestInfo = {
time: new Date().toLocaleTimeString(),
controller: context.getClass().name,
method: context.getHandler().name
};
console.log(requestInfo);
return next.handle();
}
}
Log Interceptors

42. Where to go from here

43. Freedom within the Frame
Choose your patterns

44. Freedom within the Frame
Choose your database

45. Official docs.
Community.
Build something.
Contribute.

46. Thank you!
@nirkaufman
nir@500tech.com