High Level Design - ganesh-agre/angular-ecommerce-app GitHub Wiki

πŸ›’ High-Level Design – Angular E-commerce Frontend

This High-Level Design (HLD) outlines the frontend architecture for a scalable Angular-based e-commerce application. The focus is on structuring the application to support modularity, performance, and ease of maintenance.

🧱 HLD Overview

πŸ”§ Tech Stack

  • Framework: Angular 17+
  • Routing: Angular Router
  • State Management: NgRx (or Angular Signals)
  • UI Library: Angular Material or TailwindCSS
  • HTTP Layer: Angular HttpClient (for RESTful APIs)

πŸ—‚οΈ Folder Structure

Organized using feature-based modules for clarity and scalability.

src/
β”œβ”€β”€ app/
β”‚   β”œβ”€β”€ core/             # Singleton services, guards, interceptors
β”‚   β”œβ”€β”€ shared/           # Reusable UI components (buttons, loaders)
β”‚   β”œβ”€β”€ features/
β”‚   β”‚   β”œβ”€β”€ auth/         # Login, Register pages
β”‚   β”‚   β”œβ”€β”€ user/         # User dashboard, profile, order history
β”‚   β”‚   β”œβ”€β”€ admin/        # Admin dashboard, product/order management
β”‚   β”‚   β”œβ”€β”€ products/     # Product list, details, filters
β”‚   β”‚   β”œβ”€β”€ cart/         # Cart logic and view
β”‚   β”‚   β”œβ”€β”€ wishlist/     # Wishlist logic and view
β”‚   β”‚   β”œβ”€β”€ orders/       # Shared order logic (service, models)
β”‚   β”‚   β”œβ”€β”€ checkout/     # Address selection, payment, confirmation
β”‚   └── app.component.ts  # Root layout shell
β”œβ”€β”€ assets/               # Static files (images, icons, logos)
└── environments/         # Environment-based config

🌲 Component Tree

The component hierarchy reflects the typical user flow in an e-commerce application.

AppComponent
β”œβ”€β”€ HeaderComponent
β”‚   β”œβ”€β”€ LogoComponent
β”‚   β”œβ”€β”€ NavigationLinksComponent
β”‚   β”œβ”€β”€ CartIconComponent         # Shows cart badge count
β”‚   └── UserMenuComponent         # Profile, Orders, Logout dropdown
β”œβ”€β”€ RouterOutlet
β”‚   β”œβ”€β”€ HomeComponent
β”‚   β”œβ”€β”€ ProductListComponent
β”‚   β”‚   └── ProductCardComponent
β”‚   β”œβ”€β”€ ProductDetailComponent
β”‚   β”œβ”€β”€ CartComponent
β”‚   β”‚   └── CartItemComponent
β”‚   β”œβ”€β”€ WishlistComponent
β”‚   β”œβ”€β”€ CheckoutComponent
β”‚   β”‚   β”œβ”€β”€ AddressSelectionComponent
β”‚   β”‚   β”œβ”€β”€ PaymentMethodComponent
β”‚   β”‚   └── OrderSummaryComponent
β”‚   β”œβ”€β”€ OrderHistoryComponent         # User view
β”‚   β”œβ”€β”€ AdminProductListComponent     # Admin view (uses same ProductCard)
β”‚   β”œβ”€β”€ AdminOrderListComponent       # Admin order view
β”‚   β”œβ”€β”€ LoginComponent
β”‚   └── RegisterComponent
└── FooterComponent

🧩 Feature Modules

Each module encapsulates specific business logic and UI.

Module Description
auth/ User login, register, JWT session management
user/ User dashboard, profile, address book, order history
admin/ Admin dashboard, product CRUD, order management
products/ Product listing, search, filters, detail pages
cart/ Add/remove items, cart summary, quantity controls
wishlist/ Save products for later
orders/ Shared order logic (models, services, status handling)
checkout/ Checkout flow with address selection, payment, confirmation
shared/ Common UI components, directives, pipes
core/ App-wide services, route guards, interceptors

πŸ”„ State Management

Use NgRx for structured, scalable logic, or Angular Signals for lightweight state.

Slice Description
auth Stores user session, token, roles
products Products, filters, search metadata
cart Cart items, totals, item count
wishlist Wishlist product IDs
orders User orders (history), admin orders
user Profile data, addresses

With NgRx:

  • Actions: AddToCart, LoadProducts, PlaceOrder
  • Reducers: Handle immutable state updates
  • Effects: API calls (load, create, delete)
  • Selectors: For cart total, user data, admin views

With Signals:

  • Directly use Angular’s reactive primitives for small or local slices.

🌐 Routing Structure

/
β”œβ”€β”€ /products
β”‚   └── /:id                   # Product detail
β”œβ”€β”€ /cart
β”œβ”€β”€ /wishlist
β”œβ”€β”€ /checkout
β”‚   β”œβ”€β”€ /address
β”‚   β”œβ”€β”€ /payment
β”‚   └── /summary
β”œβ”€β”€ /orders
β”‚   └── /history               # User-specific orders
β”œβ”€β”€ /user
β”‚   β”œβ”€β”€ /profile
β”‚   β”œβ”€β”€ /addresses
β”‚   └── /settings
β”œβ”€β”€ /admin
β”‚   β”œβ”€β”€ /dashboard
β”‚   β”œβ”€β”€ /products
β”‚   β”‚   β”œβ”€β”€ /                  # Admin product list
β”‚   β”‚   β”œβ”€β”€ /new               # Add product
β”‚   β”‚   └── /:id/edit          # Edit product
β”‚   └── /orders
β”‚       β”œβ”€β”€ /                  # All orders (admin view)
β”‚       └── /:id               # View/edit order
β”œβ”€β”€ /login
β”œβ”€β”€ /register

πŸ”’ Route Guards

  • AuthGuard: Required for /checkout, /wishlist, /user, /orders/history
  • RoleGuard: Protect /admin routes for admin users only

🎨 UI/UX Guidelines

  • Responsive design (CSS Grid/Flex)
  • Cart icon badge in header
  • User dropdown with "Profile", "Orders", "Logout"
  • Checkout as multi-step wizard
  • Use toasts/snackbars for feedback
  • Skeleton loaders while fetching
  • Accessible HTML (ARIA, tab indexes, keyboard nav)

πŸ›‘οΈ Best Practices

Area Practice
Performance Lazy load routes, OnPush strategy for components
Change Detection Prefer OnPush for performance gains
Security Avoid unsafe HTML, sanitize user input, use guards
Testing Unit (Jasmine), E2E (Cypress), test guards/routes/services/components
Scalability Feature-based folders, isolated modules, NgRx facades
Maintainability SRP, DRY, Angular style guide, clean module boundaries
Reliability Retry failed calls, show fallback UIs, add error boundaries/logging

πŸ” Component Reuse Tips

  • ProductCardComponent: Used in both user and admin views with an @Input() mode: 'user' | 'admin'
  • OrderListComponent: Used for both user history and admin list, filtered by role
  • ProductFormComponent: Shared for both add/edit with mode flags