React Js Study Notes

Class Components in React

Learn the legacy class-based approach to building React components, including lifecycle methods and state.

Code Splitting and Lazy Loading

Reduce initial bundle size in React apps using React.lazy and Suspense to load components on demand.

Common React Pitfalls

Frequent React mistakes — direct state mutation, bad dependency arrays, index keys, and more — with fixes.

Component Composition in React

Learn how to build complex UIs by combining small, reusable components using composition patterns.

Conditional Rendering in React

Learn the common patterns for showing or hiding UI elements based on conditions in React components.

Context API for State Management

Learn how React's built-in Context API lets you share state across components without prop drilling.

Controlled vs Uncontrolled Components

Compare controlled components, where React state drives form values, with uncontrolled components that rely on the DOM and refs.

Custom Hooks in React

Learn how to extract reusable stateful logic into your own custom hooks that follow the rules of hooks.

Dynamic Routing in React

Use URL parameters and the useParams and useNavigate hooks to build dynamic, data-driven routes in React Router.

Error Boundaries in React

Catch JavaScript errors in a component tree using class-based error boundaries and display a fallback UI instead of crashing.

Event Handling in React

Learn how React wraps native DOM events into SyntheticEvents and how to attach handlers to elements.

Form Validation in React

Implement client-side validation logic for React forms, including error state and submit-time checks.

Forms in React

Understand controlled and uncontrolled form inputs and how to manage form state in React.

Functional Components in React

Understand how to define and use functional components, the modern default building block of React apps.

History and Evolution of React

A look at how React was created at Facebook, its major milestones, and how it evolved into the modern hooks-based library it is today.

Introduction to React

A beginner-friendly overview of what React is, why it exists, and how it lets you build UIs from reusable components.

Introduction to React Hooks

Learn what React Hooks are, why they were introduced in React 16.8, and how they let function components use state and lifecycle features.

JSX Syntax and Expressions

Learn how JSX blends HTML-like markup with JavaScript to describe React UI declaratively.

Lifting State Up in React

Learn the pattern of moving shared state to the closest common ancestor so sibling components can stay in sync.

Lists and Keys in React

Learn how to render lists of elements in React and why stable, unique keys are essential for correct updates.

Nested Routes and Layouts

Build shared layouts and nested UI in React Router v6 using nested Route definitions and the Outlet component.

Prop Drilling in React

Explore the problem of passing props through many intermediate components and the patterns used to avoid it.

Props in React

Learn how props pass read-only data from parent to child components in React's one-way data flow model.

Common React Interview Questions

A curated set of frequently asked React interview questions with accurate, in-depth answers.