Design Patterns

Overview

Component

Design Pattern	Definition	Use Cases
Functional Components	Simplify components by using functions instead of classes	simple UI elements without complex logic stateless or UI-only components (like buttons, labels) rendering small reusable parts of the UI
Higher-Order Components (HOC)	Functions that take a component and return an enhanced component with additional functionality	logging enhancing existing components with additional functionality (e.g., authentication checks) sharing logic between components (e.g., logging, analytics) extending component functionality without modifying the component directly
Render Props	Components with a function as a prop that allows dynamic content rendering based on the function's output	sharing stateful logic, such as managing data-fetching toggle or switch functionality (e.g., showing/hiding elements) reusing animation logic across components
Controlled and Uncontrolled Components	Controlled components are fully managed by React state and are preferable for predictable behavior, while uncontrolled components maintain their own state	form inputs where fine control over input values is needed (Controlled) simple, self-contained forms with minimal logic requirements (Uncontrolled) cases where validation needs vary based on input type or conditions
Container and Presentational Components	Separates "smart" (container) components, which manage state and business logic, from "dumb" (presentational) components, which focus on rendering UI	large applications where separation of UI and logic is beneficial apps using state management (e.g., Redux) or context, where logic and display need decoupling optimizing re-rendering by isolating presentation logic from data handling

State Management

Design Pattern	Definition	Use Cases
Lifting State Up	When several components need to share data, the state can be lifted to their closest common ancestor and passed as props to maintain a single source of truth	sharing state between sibling components reducing redundant state variables in different components managing form data across related inputs
Context API	Allows state to be shared across components without prop drilling	providing global configuration or theme to multiple components sharing user authentication status or locale settings avoiding prop drilling in deeply nested component structures
State Colocation	Keeps the state as close to where it is needed as possible	keeping state close to where it's used (e.g., within a component) reducing unnecessary re-renders by managing state scope improving component reusability by limiting state exposure
State Reducers	Useful for managing complex state logic, often in conjunction with hooks like useReducer to handle various state transitions in a centralized way	managing complex state logic (e.g., form handling, wizards) containing state transitions in one location for predictable updates reducing repetitive state update functions in larger components

Hooks

Design Pattern	Definition	Use Cases
Custom Hooks	Encapsulate reusable stateful logic into functions that can be shared across multiple components	reusing common logic (e.g., data fetching, form handling) simplifying complex components by extracting logic managing shared logic across multiple components
UseEffect	React Hook for managing side effects in functional components, such as data fetching or subscriptions. It runs after rendering and can be controlled with a dependency array to determine when it should re-run. A cleanup function can be returned to handle cleanup tasks before the component unmounts or before the effect re-runs	executing code on component mount (e.g., API calls) cleaning up resources (e.g., removing event listeners) syncing state with external dependencies
UseMemo and UseCallback	Optimize performance by memoizing expensive calculations (useMemo) or functions (useCallback) to prevent unnecessary re-renders	optimizing performance for expensive calculations avoiding unnecessary re-renders for stable functions preventing child component re-renders in complex UIs
UseImperativeHandle	Provides a way for functional components to expose imperative methods to parent components, often used with forwardRef	exposing component functions to parent components managing custom focus control for input fields controlling animation or scroll actions externally

Code Organization

Design Pattern	Definition	Use Cases
Folder Structure	Organizes files and directories for better readability and scalability	organizing code by features, domains, or types (e.g., components, hooks) improving project scalability and team collaboration enhancing maintainability for large-scale applications
Extensible Styles	Modularizes styling in CSS (CSS-in-JS), allowing styles to be scoped to individual components	creating scoped styles to avoid CSS conflicts applying dynamic styling in JavaScript (e.g., theme-based) sharing component-specific styles in a modular fashion
Centralized Prop Types	Defines prop types for reusable components in a single location	improving type safety and readability of component props ensuring consistent prop validation across the app reducing errors from inconsistent prop usage
Service Layers	Creates a service layer for API calls, caching, or other external resources to keep components focused on UI rendering	centralizing API requests and data handling logic encapsulating external service interactions for consistency separating business logic from UI components

Data Fetching

Design Pattern	Definition	Use Cases
Fetching on Render	Triggers data fetching when a component mounts, using hooks like useEffect	basic data loading when the component mounts retrieving initial data for page rendering simplifying logic for components that don't need caching static or infrequently data changes
Fetching on Interaction	Triggers data fetching based on user interactions (e.g., clicking a button) to optimize performance	loading data only when the user initiates (e.g., button click) reducing initial load time by delaying fetches triggering data fetch on specific user actions (e.g., load more)
Data Fetching with Suspense	Uses React Suspense to manage async data fetching with loading states in a declarative way	handling loading and error states with minimal code simplifying asynchronous data handling optimizing loading experience with React Suspense features
Infinite Scrolling / Pagination	Used for loading data progressively, enhancing performance and user experience with lazy loading patterns	displaying large datasets efficiently improving UX for continuous data loading enabling smooth scrolling or pagination for long lists

Error Handling

Design Pattern	Definition	Use Cases
Error Boundaries	Components that catch JavaScript errors in their child component tree and display a fallback UI	global error handling prevents the entire app from crashing providing fallback UI for failed component rendering
Try/Catch with Async Functions	Used to handle errors in async data fetching functions, often paired with user notifications for better error management	handling errors during asynchronous operations (e.g., API calls) avoiding unhandled promise rejections logging or displaying error messages for async failures

Performance Optimization

Design Pattern	Definition	Use Cases
Lazy Loading and Code Splitting	Loads only the required modules at a time, often using React.lazy and Suspense to delay component loading until needed	loading components only when needed (e.g., dynamic imports) reducing initial page load times for faster interaction enhancing performance by splitting large bundles
Virtualization	Renders only visible items in a large list, improving performance for large data sets	rendering only visible items in long lists reducing DOM elements to improve performance efficiently handling large datasets in list or table views
Memoization	Optimizes components with React.memo or useMemo to avoid re-rendering when props or state haven't changed	caching expensive calculations or API results reducing unnecessary re-renders by using stable values improving performance for complex computations in real time
Throttling and Debouncing	Controls the rate at which functions like API calls are executed, reducing unnecessary re-renders or data fetching	limiting function executions in rapid interactions (e.g., resize) improving input performance by delaying actions optimizing resource usage in frequent events (e.g., scroll)

Routing

Design Pattern	Definition	Use Cases
Nested Routing	Creates a hierarchy of routes, allowing sub-routes to be rendered inside parent routes	defining routes that need hierarchical structure managing parent-child relationships in route paths building layouts where pages have nested views
Dynamic Routing	Allows routes to change based on state or data	loading routes based on dynamic parameters (e.g., user ID) creating flexible route structures for user-generated content user-specific or resource-specific routes
Protected Routes	Guards routes that require authentication, often wrapping them with an authentication check component	restricting access to authenticated users only redirecting unauthenticated users to login pages securing sensitive pages with conditional access
Lazy Loading Routes	Delays loading of route-based components until they're needed, improving load times and reducing initial bundle size	loading routes only when they're accessed reducing initial app bundle size optimizing route handling for large applications

Miscellaneous

Design Pattern	Definition	Use Cases
Portals	Renders components outside of the main React tree	rendering modals, tooltips, or dropdowns outside the parent DOM managing z-index and overlay issues ensuring elements appear above the rest of the UI
Compound Components	Creates a group of components that work together, like <Tabs/> and <Tab/>, where the parent component manages the state of its children	creating components with flexible subcomponents (e.g., tabs) enabling users to customize the structure within the main component providing a consistent API for complex component patterns
Configuration-Driven UI	Allows components to be rendered based on configuration objects, making UI structure flexible and customizable	building UI based on JSON or configuration files creating reusable and customizable forms or tables separating UI structure from hardcoded layouts
Facade	Provides a simplified interface to complex logic, often wrapping multiple hooks or components for simplified usage	simplifying complex functionality with a single interface abstracting library methods into app-specific functions managing third-party service integrations efficiently