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Luis M. Frazier
Luis M. Frazier

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10 Main Core Concepts You Need to Know About React

10 Main Core Concepts You Need to Know About React

Are you diving into the world of React, the popular JavaScript library for building user interfaces? React is a powerful tool for creating dynamic, efficient, and interactive web applications. To help you get started on the right foot, let's explore ten core concepts that are essential for every React developer to grasp.

What Is React?

Understanding React

Before we dive into the specifics, it's crucial to understand what React is. React is an open-source JavaScript library used for building user interfaces or UI components. It was developed by Facebook and is now maintained by Facebook and a community of individual developers and companies.

React in a Nutshell

React simplifies the process of creating interactive and dynamic user interfaces by breaking them down into smaller, reusable components. It allows developers to efficiently update and render components when data changes, all while maintaining optimal performance.


The Building Blocks of React

Components are the heart and soul of React. Everything you see on a React application is a component. Components are reusable, self-contained units of code responsible for rendering a part of the user interface.

Class Components vs. Functional Components

React components can be either class components or functional components. Class components use ES6 class syntax, while functional components are simple JavaScript functions. Functional components, with the introduction of React Hooks, have become more prevalent due to their simplicity and flexibility.

Virtual DOM

The Key to React's Efficiency

The Virtual DOM is one of React's most significant innovations. It's a lightweight, in-memory representation of the actual DOM. React uses the Virtual DOM to optimize the updating of the actual DOM, resulting in improved performance.

Reconciliation Process

React's Virtual DOM works by creating a virtual tree, diffing it with the previous tree, and then updating the actual DOM only with the necessary changes. This process, known as reconciliation, ensures that updates are both efficient and fast.

JSX - JavaScript XML

Mixing JavaScript with HTML

JSX, or JavaScript XML, is a syntax extension for JavaScript. It allows you to write HTML-like code within your JavaScript files, making it easier to describe what the UI should look like.


JSX code needs to be transpiled into standard JavaScript using tools like Babel before it can be executed by web browsers. This step ensures browser compatibility.

State and Props

Managing Data in React

State and props are fundamental concepts in React for managing data and communication between components.


State represents the data that should be saved and modified within a component. When state changes, React re-renders the component to reflect those changes.


Props, short for properties, are a way to pass data from a parent component to a child component. They are read-only and help make your components more reusable.

Lifecycle Methods

The Lifecycle of a Component

React components go through a series of lifecycle methods, which allow you to execute code at specific points during a component's existence.

componentDidMount and componentDidUpdate

The componentDidMount method is called after a component is rendered, making it a suitable place for performing initial setup. componentDidUpdate is invoked after a component's update.

React Hooks

Simplifying State Management

React Hooks, introduced in React 16.8, provide a way to use state and other React features in functional components without writing a class.

useState and useEffect

useState allows you to add state to your functional components, while useEffect helps you perform side effects in your functions.

Conditional Rendering

Showing or Hiding Components

Conditional rendering is the practice of showing or hiding components based on certain conditions. It's a crucial concept for building dynamic user interfaces.

Conditional Operators

In React, you can use conditional operators, such as the ternary operator or if statements, to determine what gets rendered based on specific conditions.

Event Handling

Interactivity with Users

Event handling in React enables you to capture and respond to user interactions, such as clicks, input, and more.

Handling Events

In React, you can use event handlers to define functions that respond to events triggered by the user. Common events include onClick, onChange, and onSubmit.

Managing State

Centralizing State Management

As your application grows, managing state across components becomes a challenge. Tools like Redux and the Context API help centralize state management.


Redux is a state management library that allows you to store and manage global state in a predictable way. It's commonly used in larger React applications.


Mastering these ten core concepts in React will provide a solid foundation for your journey as a React developer. React's efficiency, component-based architecture, and powerful state management capabilities make it a versatile and popular choice for building modern web applications. Whether you're creating a small personal project or working on a large-scale application, React's principles will serve you well in your development endeavors. Happy coding!

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