React.js last minutes points to revise before going for interview

 1) Hooks:

useState: Manages state in functional components. useEffect: Handles side effects in functional components. useContext: Accesses the context in functional components. useReducer: Manages complex state logic with a reducer function. useMemo: Memoizes values to optimize performance. useCallback: Memoizes callback functions to prevent unnecessary renders. useRef: Creates a mutable object that persists between renders. 2) Higher Order Components (HOC): What?: Functions that take a component and return an enhanced version. When?: Reuse component logic, share code, or manipulate component behavior. Why?: Promotes code reusability and separation of concerns. How?: Wrap a component with a function that adds or modifies its behavior. 3) Life Cycle Methods of Components: Class Components: Traditional React components using ES6 classes. Mounting: Component is being created and inserted into the DOM. Updating: Component is being re-rendered as a result of changes. Unmounting: Component is being removed from the DOM. 4) State management (all about data): State/Props: Internal state for a component/external data passed to a component. Props drilling: Passing props through multiple layers of components. Context: Provides a way to pass data through the component tree without passing props. 5) Redux or Zustand: How redux works?: Centralized state management using actions and reducers. Why?: For managing complex application states. When?: In large applications with a need for a single source of truth. Redux Toolkit (RTK): Simplifies Redux setup and usage. 6) Custom Hooks: When to use?: Extracting and reusing component logic. Code: Functions prefixed with "use" returning stateful logic. Why?: Enhances code organization, reusability, and readability. 7) Lazy Loading: Code splitting: Breaking down the application into smaller parts. Chunking: Loading only the necessary code chunks. Suspense: Pausing rendering until a component is ready. 8) Virtual DOM: Reconciliation Algorithm: Efficiently updates the UI based on state changes. React Fiber: A reimplementation of React's core algorithm. Renders: The process of updating the virtual DOM. Diff algorithm: Compares the previous and current state to determine changes. How does render work?: Updating the UI based on virtual DOM changes. 9) SSR vs CSR (important): What?: Server-Side Rendering vs. Client-Side Rendering. Difference: Where rendering occurs - server or client. SEO and performance (SSR): Improved search engine optimization and initial load speed. 10) Routing (Role-based access control-RBAC): react-router: Library for handling navigation in React applications. How do you manage protected routes?: Utilize authentication and authorization checks. How do you handle routes?: Define routes and components for navigation. Query params: Additional information passed in the URL. Dynamic routing: Creating routes dynamically based on data. 11) Testing: React Testing Library: Testing library for React applications. Unit Testing: Testing individual units of code. Hack for interview: Emphasize writing testable code and demonstrate test cases. 12) Async Tasks: API Calls: Fetching data from external sources. useEffect in depth: Managing side effects, including async operations. Events: Handling asynchronous events. Promises: A pattern for handling asynchronous operations. setTimeout: Delaying the execution of code. 13) Reusability, Readability, modularity, testability (Coding Practices): 14) Performance: Lazy loading: Loading resources only when needed. Asset optimization: Minifying and compressing JS/CSS code. Writing optimized code: Following best practices for efficient code. Bundler: Tools like Webpack to bundle and optimize code. CDN / Server level: Distributing assets for faster loading. Rendering of components: Optimizing rendering for better performance. 15) Styling: Tailwind, StyleX, Bootstrap, Material UI, Ant UI, CSS / SCSS: Different styling approaches and libraries.