ReactJS

ReactJS Dev Tools

React DevTools helps developers inspect the component tree, props, state, hooks, and rendering behavior. It is one of the most important tools for diagnosing React applications. Components panel

ReactJS

TypeScript with React

TypeScript gives React applications compile-time checks for props, state, API models, events, hooks, and reusable components. It is especially valuable in large teams because it makes contracts between components and services explicit.

ReactJS

CORS and CSRF

CORS and CSRF solve different problems. CORS controls whether browser JavaScript is allowed to read cross-origin responses. CSRF protects cookie-authenticated applications from unwanted state-changing requests initiated by an attacker-controlled site.

ReactJS

Authentication & Authorization

Authentication identifies a user. Authorization determines what that user is permitted to do. A production React application normally handles authentication state, protected routes, session expiration, permission-based UI, and API authorization while relying on the backend as the security authority.

ReactJS

API Integration — REST, Axios, Error Handling & Loading States

A production React application usually communicates with backend APIs. Good API integration is more than calling fetch or Axios.

ReactJS

Forms & Validation — React Hook Form + Validation

React Hook Form is a popular form-management library designed to simplify form state, validation, submission, and field registration.

ReactJS

State Management — Context API vs Redux Toolkit

React applications start with local component state, but larger applications often need shared state. Context API and Redux Toolkit solve different problems.

ReactJS

Render Props & Compound Components

Render Props and Compound Components are two important React composition patterns. Render Props focus on sharing behavior by allowing the consumer to provide a rendering function. Compound Components focus on creating a group of components that work together through shared state and context.

ReactJS

Controlled vs Uncontrolled Components

Forms are one of the clearest places to understand the difference between React state and the DOM itself. In a controlled component, React state is the source of truth for the input value. In an uncontrolled component, the DOM keeps the current value and React reads it when required.

ReactJS

useReducer — Complex State Management

useReducer manages state through a reducer function and dispatched actions. It is useful when many related state transitions need clear, centralized rules.

ReactJS

useContext — Global State & Dependency Sharing

Context makes a value available to components below a provider without manually passing it through every intermediate component.

ReactJS

Destructuring, Spread & Rest Operators

Destructuring, spread syntax, and rest syntax are used constantly in React code. They make it easier to work with props, state objects, arrays, function parameters, and immutable updates.

ReactJS

State in ReactJS

useRef and useMemo solve very different problems. useRef provides a persistent mutable reference whose changes do not normally trigger a render, while useMemo caches the result of a calculation between renders.

ReactJS

Conditional Rendering

Real applications rarely display the same UI all the time. A screen may show a loading message while data is being fetched, an error when a request fails, an empty state when there are no records, or a list when data is available. React uses normal JavaScript expressions and control flow patterns to handle these situations.

ReactJS

ReactJS Props

useState is a React Hook used to add state to a function component. State represents information that can change over time and whose changes may require the component UI to update.

ReactJS

Props and state

React Hooks are functions that let function components use React features such as state, effects, references, context, and other capabilities.

ReactJS

React component

Real applications rarely display the same UI all the time. A screen may show a loading message while data is being fetched, an error when a request fails, an empty state when there are no records, or a list when data is available.

ReactJS

Components and JSX

Props and state are fundamental concepts for managing data in React. Props allow a component to receive data from its parent, while state allows a component to manage data that can change over time.

ReactJS

What is React?

React is a JavaScript library for building user interfaces, especially applications where the screen changes frequently based on user actions and application state.

System Design - Concepts

REST API — How Do Applications Communicate Over HTTP?

REST (Representational State Transfer) is an architectural style used to design APIs that allow applications to communicate over HTTP.