Getting started with React

React has become a cornerstone of modern front-end development as of 2025. This guide covers everything from understanding React’s purpose and history to learning its core concepts like the component lifecycle, essential hooks, and built-in components you need to know. Comprehensive code examples and direct references to the official React documentation are included to help you with the right pointers.

For the purposes of the code snippets found in this article, I recommend using Vite’s react-ts template with pnpm create vite my-react-app --template react-ts.

Table of Contents

1. Glossary
2. Introduction to React
3. Brief History of React
4. Deep Dive into the Component Lifecycle
5. Must-Know Hooks
6. Essential Components
7. Final Considerations

Glossary

• UI: User Interface
• DOM: Document Object Model

Introduction to React

React is a JavaScript library for building user interfaces, primarily for web applications. It solves the problem of creating interactive, dynamic UIs by enabling developers to build encapsulated components that manage their own state and compose them into complex interfaces. React’s declarative nature means you describe what your UI should look like for any given state, and React efficiently* updates and renders the right components when your data changes. This makes your code more predictable, easier to debug, and easier to maintain.

For further reading, consult the official React documentation: React Docs.

Brief History of React

React was initially released by Facebook in 2013 to address the challenges of building large, dynamic web applications with complex user interfaces. It introduced innovative concepts such as the virtual DOM and component-based architecture, allowing developers to create responsive and maintainable UIs.

Over the years, React has evolved through continuous improvements, including the introduction of hooks in 2019, which revolutionized state and lifecycle management in functional components. The ecosystem matured towards fully functional components by now - 2025, deprecating most class-based components in favor of simpler, hook-centric patterns.

Deep Dive into the Component Lifecycle

React, in its 19th version - released in December 2024, functional components paired with hooks have mostly replaced class components, but understanding component lifecycle is still crucial as hooks abstract these lifecycle phases. Here is a breakdown:

• Mounting: The component is created and inserted into the DOM.
• Updating: When props or state change, the component re-renders.
• Unmounting: The component is removed from the DOM.

In functional components, useEffect hook covers the lifecycle:

import React, { useEffect } from 'react';

function Example() {
  useEffect(() => {
    // ComponentDidMount and ComponentDidUpdate logic here

    return () => {
      // ComponentWillUnmount logic here
    };
  }, []); // Empty dependency array means runs once on mount and cleanup on unmount

  return <div>Lifecycle in React with useEffect</div>;
}

This hook handles side effects, subscriptions, and cleanup, replacing several lifecycle methods from class components.

More details on lifecycle and hooks are available here: React Docs - Hooks at a Glance.

Must-Know Hooks

React’s hooks API is foundational in 2025. Key hooks every React developer should know include:

• useState: Manage local component state.
• useEffect: Handle side effects and lifecycle events.
• useContext: Access context for global state.
• useReducer: Manage complex state logic.
• useMemo and useCallback: Optimize performance by memoizing values and functions.

Example of useState and useEffect:

import React, { useState, useEffect } from 'react';

function Counter() {
  const [count, setCount] = useState(0);

  useEffect(() => {
    document.title = `Count: ${count}`;
  }, [count]); // Runs when count changes

  return (
    <button onClick={() => setCount(count + 1)}>
      You clicked {count} times
    </button>
  );
}

Explore all hooks here: React Docs - Built-in React Hooks.

Essential Components

In 2025, React developers primarily work with functional components, which are simple JavaScript functions returning JSX. Core patterns and components include:

• Functional Components: Small, reusable pieces of UI.
• Higher-Order Components (HOCs): Functions that take a component and return an enhanced component.
• Error Boundaries: Special components to catch JavaScript errors (mostly class-based, but used sparingly).
• Fragments: Used to group multiple elements without adding extra nodes to the DOM.

Example of a functional component:

// Greeting is a function that accepts an object as parameter.
// The object holds component props.
function Greeting({ name }) {
  // the "name" prop is then reused in the component JSX output.
  return <h1>Hello, {name}!</h1>;
}

Use Fragments to avoid extra nodes:

function List() {
  return (
    <> {/* here is a fragment opening tag */}
      <li>Item 1</li>
      <li>Item 2</li>
    </> {/* here is a fragment closing tag */}
  );
}

There are other important components, such as Suspense and the newly introduced Activity, worth learning about. More details on components: React Docs - Built-in React Components.

Final Considerations

React in 2025 revolves around simplicity, modularity, and hooks-powered functional components. Mastering React means understanding how to build composable UI components, manage state with hooks, and use the lifecycle abstracted through useEffect. This approach yields cleaner, more maintainable, and scalable codebases. Start small, follow best practices, and use the official React documentation as your definitive resource to deepen your expertise. I hope this article helps understanding the core concepts of implementing web interfaces using React.

Leave a comment if you’d like a follow up in React.

See ya! 👋