How imykhailychenko/online-shop works
<explanation>
1. Identify the project type and purpose
• This is a full‑stack online shop application (“Online Shop”)
• Frontend: React + TypeScript + Redux + Saga
• Backend: Nest.js + TypeScript + Node.js + TypeORM
• Database: PostgreSQL
• Deployed on Heroku (backend) and serves a React SPA
2. Analyze the file structure
Top‐level:
• client/ – React single‑page app
– src/ (components, hooks, store, assets, styles, interface definitions)
– public/ (static HTML, manifest, robots.txt)
– build & lint configs
• server/ – Nest.js backend
– src/ (modules: auth, products, pictures, uploads, users)
– Each module: controller(s), service(s), DTOs, entities
– TypeORM entities in products/entities and users
– Main entry: src/main.ts, src/app.module.ts
– Tests: e2e + unit specs
• Root: build.sh, dev.sh, prod.sh, Procfile (Heroku), package.json
3. Examine the README for insights
• Technology stack listed
• Notes on Heroku free‐dyno sleep behavior
• No architecture diagram present
4. Instructions for drawing the system design diagram
a. Main components (draw as separate boxes):
1. User’s Browser (Client)
2. React Frontend (client/)
3. API Gateway or Edge (Heroku Router / Procfile)
4. Nest.js Backend (server/)
– Modules: Auth, Products, Pictures, Uploads, Users
5. PostgreSQL Database
6. (Optional) Static Asset Store or File Storage (if pictures/uploads saved externally)
7. External Services (e.g., Heroku, CDN)
b. Relationships & interactions:
• User’s Browser ↔ React Frontend
– Client serves static bundle (index.html + JS/CSS)
– React‑Router handles client‑side routing
• React Frontend → Nest.js Backend
– HTTP(S) calls to endpoints: /auth, /products, /pictures, /uploads, /users
– Redux‑Saga manages side effects and dispatches API calls
• Nest.js Backend ↔ PostgreSQL
– TypeORM mediates entity→table mapping
– Repositories used in services to CRUD data
• Nest.js Modules communicate internally
– Controllers invoke Services
– Services interact with repositories or other services
• (If present) Uploads Module → File System or Cloud Storage
c. Architectural patterns / design principles:
• Frontend: Component hierarchy + container/presentational pattern
• State management: Redux (store/, slices), Saga for async flows
• Backend: Modular MVC (Controllers, Services, Modules)
• Layered architecture: Presentation (controllers) → Business (services) → Data (repositories/entities)
• Dependency injection (Nest.js)
• Configuration management via environment files
d. Relevant technologies / frameworks:
• React / React Router / Redux / Redux‑Saga
• Nest.js / TypeORM
• PostgreSQL
• Heroku (deployment)
• ESLint, Prettier, TypeScript
• Build scripts (build.sh, Procfile)
5. Tailoring the diagram for a full‑stack application
• Draw two main tiers: Frontend (client) and Backend (API + DB)
• Emphasize boundaries:
– Client static hosting (Heroku or CDN)
– API layer (Nest.js)
– Data layer (PostgreSQL)
• Indicate cross‑cutting concerns:
– Auth flow: Login/Join → JWT or session
– File uploads: client → /uploads endpoint → storage
6. Diagram elements & styling guidelines
• Boxes with clear labels: “React App”, “Auth Module”, “Products Module”, “PostgreSQL”
• Arrows with direction & labels:
– “HTTP(S) GET/POST /products”
– “TypeORM queries”
• Color coding / shapes:
– Frontend (blue rectangles)
– Backend modules (green rectangles)
– Database (cylinder or orange)
– External services/infrastructure (grey)
• Group backend modules inside a larger “Nest.js Backend” boundary
• Use swimlanes or layers to separate presentation, business, and data
7. Emphasis on detail
• Capture all backend modules: Auth, Users, Products, Pictures, Uploads
• Show Redux store shape (auth, cart, products, pictures, uploads slices)
• Annotate environment/config files driving behavior (client/.env, server/.env)
• Highlight build & deployment scripts (Procfile, build.sh, dev.sh, prod.sh)
Following these guidelines will ensure a detailed, accurate, and tailored system design diagram for this full‑stack online shop.