Core Code
Core Code Modern Dev Handbook
REACT Contents
React Fundamentals
React Architecture Overview JSX and Rendering Model Component Design Principles Props and Data Flow State Management with useState Side Effects with useEffect Event Handling Patterns Conditional Rendering Strategies Lists, Keys, and Reconciliation Forms and Controlled Components Component Composition Lifting State and Shared State Basic Routing with React Router Failure Modes in Beginner React Apps
React + TypeScript
Typing Functional Components Typing Props and Children useState and Type Inference useReducer with Type Safety Typing Event Handlers Generic Components Utility Types in React Discriminated Unions for UI State Strict Mode and Null Safety API Response Typing Strategies Form Typing Patterns Avoiding any and Unsafe Casts Type-Safe Context API Failure Modes in React + TypeScript
React Advanced Patterns
Custom Hooks Architecture Context vs Prop Drilling Tradeoffs Compound Components Pattern Controlled vs Uncontrolled Abstractions Render Props and Pattern Alternatives State Machines in React Performance Optimization Playbook Memoization Strategies Code Splitting and Lazy Loading Error Boundaries and Recovery Portal Architecture Large Scale Folder Structure Testing Strategy: Unit and Integration Common React Anti Patterns
React Production
CSR vs SSR vs SSG Hydration and Mismatch Failures Next.js Architecture Overview App Router Deep Dive Authentication Patterns Token Storage Security Role Based UI Control API Integration Patterns Rate Limiting and UI Resilience Frontend Security Checklist XSS in Modern React Observability in Frontend Bundle Optimization Production Incident Playbook
Distributed Systems
Distributed System Fundamentals CAP Theorem in Practice Consistency Models Replication Strategies Leader Election Concepts Consensus Algorithms Overview Event Driven Architectures Message Queues and Delivery Guarantees Idempotency Patterns Saga Pattern Circuit Breakers Backpressure and Flow Control Observability in Distributed Systems Failure Scenarios and Postmortems

Next.js Architecture Overview

Next.js is a production framework for React with routing, data fetching, rendering modes, and deployment primitives. Learn core building blocks, boundary rules, and operational risks in large codebases.
On this page

What Next.js Adds

  • File based routing and layouts.
  • Multiple rendering modes per route: SSR, SSG, ISR, CSR.
  • Built in bundling, code splitting, and optimization.
  • Production deployment primitives: edge, server, and static output.

Core Building Blocks

  • Routes: pages or app router segments.
  • Layouts: stable shell boundaries.
  • Data fetching: server side loading strategies.
  • API routes: server endpoints when used.
  • Middleware: request time routing and auth gates.

Boundary Rules

  • Keep route shells stable and isolate expensive trees.
  • Do not leak transport DTOs into UI components.
  • Separate server only logic from client components clearly.
  • Define caching and revalidation rules explicitly per route.

Operational Concerns

  • Cache control and revalidation are part of correctness.
  • Misconfigured caching can leak personalized content.
  • Build time and bundle size must be monitored continuously.

Deployment Model

  • Static assets are served via CDN.
  • Server rendering can run on Node or Edge runtimes depending on configuration.
  • Monitoring must include server latency, edge cache hit rate, and client metrics.

Failure Modes

  • Route level caching leaks user specific HTML or data.
  • Hydration warnings due to mixing server and client only rendering.
  • Large bundles due to shared imports and missing boundaries.
  • Slow builds due to unbounded static generation and heavy data transforms.

Production Checklist

  • Route strategy documented: SSR, SSG, ISR, CSR by page.
  • Caching and revalidation rules tested and monitored.
  • Server and client boundaries are explicit.
  • Bundle size budgets and build time budgets exist.
App Router Deep Dive →