Sustainable SPA with DDD - The beginning of a wonderful friendship?

@ManfredSteyer Sustainable SPA with DDD The beginning of a wonderful
friendship? angular-architects.io

What do we need for a good architecture? Experience

@ManfredSteyer Domain Driven Design

@ManfredSteyer How to create sustainable frontend architectures with ideas from
DDD? ?

@ManfredSteyer Contents 1) DDD in a Nutshell 2) Monorepos 3)
Monorepos & DDD 4) DDD & Micro Frontends

@ManfredSteyer About me… • Manfred Steyer ANGULARarchitects.io • Angular Trainings
and Consultancy • Google Developer Expert (GDE) • Trusted Collaborator in the Angular Team Page ▪ 8 Manfred Steyer Public: Frankfurt, Munich, Vienna In-House: everywhere http://softwarearchitekt.at/workshops

@ManfredSteyer 1) DDD in a nutshell

@ManfredSteyer Domain Driven Design Strategic Design Tactical Design Decomposing a
System Design Patterns & Practices

@ManfredSteyer This is what Strategic DDD prevents

@ManfredSteyer Example e-Procurement System

@ManfredSteyer Catalog Approval Specification Ordering Example Sub-Domains

@ManfredSteyer 2) Monorepos

@ManfredSteyer Workspace

@ManfredSteyer Advantages No version conflicts No burden with distributing libs

@ManfredSteyer Moving back and forth Npm Registry

@ManfredSteyer https://nrwl.io/nx

@ManfredSteyer Visualize Module Structure

@ManfredSteyer 3) Nx Monorepos and Strategic Design

@ManfredSteyer Catalog Ordering Shared Feature Feature Feature Feature Feature UI
UI UI UI UI UI UI UI UI Domain Domain Domain Domain Domain Domain Util Util Util Util Util Util Enterprise Monorepo Patterns, Nrwl 2018: https://tinyurl.com/y2jjxld7 @ManfredSteyer Shared Kernel (if really needed) & other libs Smart Comp. Dumb Comp.

@ManfredSteyer Catalog Ordering Shared Feature API Feature Feature Feature Feature
UI UI UI UI UI UI UI UI UI Domain Domain Domain Domain Domain Domain Util Util Util Util Util Util @ManfredSteyer

@ManfredSteyer Application Domain Infrastructure Isolate your domain! Domain e. g.
data access Use case specific facades, state management Entities, biz logic

@ManfredSteyer Alternatives to layering • e. g. Hexagonal Architecture, Clean
Architecture • Anyway: We need to restrict access b/w libraries

@ManfredSteyer DEMO

@ManfredSteyer BLOG ANGULARarchitects.io

@ManfredSteyer Finegrained Libraries • Unit of recompilation • Unit of
retesting • Access restrictions • Information Hiding

@ManfredSteyer Facades and State Management

@ManfredSteyer Facade (Application Service) @Injectable({ providedIn: 'root' }) export class
ProductFacade { […] }

ProductFacade { public products: Product[] = []; […] } State!

ProductFacade { public products: Product[] = []; constructor(private productService: ProductService) { } […] }

ProductFacade { public products: Product[] = []; constructor(private productService: ProductService) { } search(category: string): void { […] } }

ProductFacade { public products: Product[] = []; constructor(private productService: ProductService) { } search(category: string): void { […] } } SPA has to pull :-(

ProductFacade { public products: Observable<Product[]>; constructor(private productService: ProductService) { } search(category: string): void { […] } } Also key for messaging

@ManfredSteyer App Home Catalog Search RatingFacade ProductFacade SearchFacade Facades Have
State

@ManfredSteyer App Home Catalog Search RatingFacade ProductFacade SearchFacade Facades Have
State Store (z. B. Redux/ NGRX) Observable Action

@ManfredSteyer Entities & Aggregates

@ManfredSteyer Entity/ Aggregate Root (OOP) public class BoardingList { private
int id; private int flightId; private List<BoardingListEntry> entries; private boolean completed; // Getters and Setters public void setStatus(int passengerId, BoardingStatus status) { // Complex logic to update status } }

FP und DDD?

@ManfredSteyer Entities (FP) export interface BoardingList { readonly id: number;
readonly flightId: number; readonly entries: BoardingListEntry[]; readonly completed: boolean; } export function updateBoardingStatus( boardingList: BoardingList, passengerId: number, status: BoardingStatus) { // Complex logic to update status }

@ManfredSteyer 4) Micro Frontends

@ManfredSteyer Catalog Ordering Shared Feature Feature Feature Feature Feature …
… … … … … … … … @ManfredSteyer e-Procurement App Deployment Monolith

… … … … … … … … @ManfredSteyer Catalog App Ordering App Option 1: One App per Domain

… … … … … … … … @ManfredSteyer Catalog App Ordering App Option 2: One Monorepo per Domain Publish shared libs seperately via npm Different Versions

@ManfredSteyer BLOG ANGULARarchitects.io

Summary • Slicing into sub-domains • Slicing into layers •
Finegrained libraries • Enforce restrictions • Fits to micro frontends

@ManfredSteyer

@ManfredSteyer Contact and Downloads [web] ANGULARarchitects.io [twitter] ManfredSteyer d Slides
& Examples Public: Frankfurt, Munich, Vienna In-House: everywhere http://softwarearchitekt.at/workshops

Sustainable SPA with DDD - The beginning of a w...

Sustainable SPA with DDD - The beginning of a wonderful friendship?

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