1  Introduction to System Design

1.1 Overview

System design is the process of defining the architecture, components, modules, interfaces, and data for a system to satisfy specified requirements. In the context of web applications, system design encompasses everything from choosing the right database to designing scalable microservices architectures.

1.2 Working Components of Front-end Architecture

Successful web applications require well-architected front-end systems. Here are the key components:

1.2.1 Code

  • HTML5/WAI-ARIA: Semantic markup and accessibility standards
  • CSS/Sass: Code standards and organization for maintainable stylesheets
  • Object-Oriented approach: How components break down and compose together
  • JavaScript frameworks: Modern frameworks, code organization, and performance optimization techniques
  • Asset Delivery: Front-end operations and optimization strategies

1.2.2 Documentation

  • Onboarding Documentation: Getting new developers up to speed
  • Styleguide/Pattern Library: Consistent UI components and patterns
  • Architecture Diagrams: Code flow, tool chain, and system interactions

1.2.3 Testing

  • Performance Testing: Measuring and optimizing application performance
  • Visual Regression: Catching unintended UI changes
  • Unit Testing: Testing individual components
  • End-to-End Testing: Testing complete user workflows

1.2.4 Process

  • Git Workflow: Version control strategies and branching models
  • Dependency Management: Using npm, Bundler, Bower, etc.
  • Build Systems: Automation with Grunt, Gulp, Webpack, etc.
  • Deploy Process: Continuous delivery and deployment strategies
  • Continuous Integration: Automated testing with Travis CI, Jenkins, etc.

1.3 Web App System Design Considerations

When designing modern web applications, consider these critical aspects:

1.3.1 Security (CORS)

Cross-Origin Resource Sharing (CORS) is a security feature that restricts how resources on a web page can be requested from another domain. Proper CORS configuration is essential for secure API communication.

1.3.2 Using CDN

A Content Delivery Network (CDN) is a system of distributed servers that deliver web content to users based on their geographic location.

Benefits of CDN:

  • Speeds up content delivery by serving from geographically closer servers
  • Reduces load on origin servers
  • Provides protection from traffic surges and DDoS attacks
  • Improves global reach and availability

1.3.3 Full Text Search

Implementing efficient search using engines like Sphinx, Lucene, or Solr. These achieve fast search responses by searching an index instead of the raw text directly.

1.3.4 Offline Support/Progressive Enhancement

  • Service Workers: Enable offline functionality and background sync
  • Progressive Web Apps (PWA): Providing app-like experiences in browsers

1.3.5 Web Workers

Use Web Workers to run JavaScript in background threads, preventing UI blocking during heavy computations.

1.3.6 Server Side Rendering (SSR)

Rendering pages on the server improves:

  • Initial page load performance
  • Search engine optimization (SEO)
  • Social media sharing with proper meta tags

1.3.7 Asynchronous Loading of Assets (Lazy Loading)

Load resources only when needed to improve initial page load time and reduce bandwidth usage.

1.3.8 Minimizing Network Requests

Techniques include:

  • HTTP/2 multiplexing
  • Resource bundling
  • CSS sprites
  • Image optimization

1.3.9 Developer Productivity/Tooling

Invest in:

  • Modern build tools
  • Hot module replacement
  • Linting and formatting
  • Debugging tools

1.3.10 Accessibility

Ensure your application is usable by people with disabilities:

  • Keyboard navigation
  • Screen reader support
  • Color contrast
  • ARIA labels

1.3.11 Internationalization (i18n)

Design for multiple languages and locales from the start:

  • Externalized strings
  • Date/time formatting
  • Number formatting
  • Right-to-left (RTL) support

1.3.12 Responsive Design

Create interfaces that work across different:

  • Screen sizes
  • Device types
  • Orientations
  • Input methods (touch, mouse, keyboard)

1.3.13 Browser Compatibility

Test and ensure functionality across:

  • Different browsers (Chrome, Firefox, Safari, Edge)
  • Browser versions
  • Mobile browsers
  • Legacy browser support strategies

1.4 Summary

This chapter introduced the fundamental considerations for designing web applications. The following chapters will dive deeper into distributed systems principles, architectural patterns, and the specific components that make up scalable systems.