Building A SPA in React: Key Concepts Explained

Creating a Single Page Application (SPA) in React might seem tricky at first, but once you understand the key concepts, it all starts to click. SPAs offer a fast, seamless user experience by loading content dynamically without refreshing the page. That’s why they power everything from social media platforms to modern web apps.

In this blog, we’ll break down the essential concepts behind SPAs in React—components, state management, routing, performance optimization, and more. Whether you're just starting out or looking to refine your skills, you’ll walk away with a solid understanding of how to build a smooth, high-performing React SPA.

Let’s dive in!

What is SPA in React?

A Single Page Application (SPA) in React is a web app that dynamically updates the current web page instead of loading entire new pages from the web server. This approach ensures a seamless user experience by eliminating unnecessary page reloads and improving performance.

When building a react single page application, developers use React Router to manage navigation between different views within a single html page. The react router dom package helps maintain multiple pages within a single page app, making navigation feel smooth.

Is React SPA or SSR?

React itself is a JavaScript library for building user interfaces, and it supports both Single Page Applications (SPA) and Server-Side Rendering (SSR).

• React SPA: The entire app runs in the browser, and navigation happens without reloading the entire page.

• Server Side Rendering (SSR): The web application is pre-rendered on the web server before being sent to the client.

Most React applications are built as SPAs using create react app, but SSR is beneficial for SEO and initial load performance.

Why is SPA Used?

A single page application (SPA) offers several advantages over traditional web applications, making it a preferred choice for modern react projects. Here’s why:

1. Fast Loading Websites: SPAs load content dynamically, reducing the need to fetch an entire html file every time a user navigates.

2. Seamless User Experience: Users experience smooth navigation without waiting for full-page refreshes.

3. Efficient State Management: SPAs handle data efficiently using tools like React’s state management and API integrations.

4. Better Developer Experience: Using React Router Dom, developers can create a structured directory structure that keeps the src folder organized.

5. Reduced Server Load: Since SPAs only request data instead of full web pages, the web server experiences lower traffic.

What is SPA in JavaScript?

A single page application (SPA) in JavaScript is a web app that updates only specific sections of a single html document instead of reloading new web pages. React is widely used to build react SPA by utilizing react router for handling multiple pages within the same js file.

In JavaScript, SPAs leverage technologies like:

• React Router: Enables seamless navigation between views.

• API Calls: Fetch dynamic data from servers.

• State Management: Maintain user data across user requests.

By using install react router dom, developers can enhance their react single experience, ensuring smooth navigation between sections of a web application.

Building a React SPA

To create a react single page application, follow these steps:

1. Install Create React App

Use the following command to set up a new react project:

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1npx create-react-app my-app

This will generate the default files needed for the project.

2. Install React Router

Run the following command to install react router dom:

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1npm install react-router-dom

Or use:

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1npm install react router

This will allow navigation between multiple pages in a react single experience.

3. Setup Routing in App.js

Modify the app component by importing React Router and setting up routes:

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1import React from "react";
2import { BrowserRouter as Router, Route, Switch } from "react-router-dom";
3import Home from "./Home";
4import Contact from "./Contact";
5
6function App() {
7  return (
8    <Router>
9      <Switch>
10        <Route exact path="/" component={Home} />
11        <Route path="/contact" component={Contact} />
12      </Switch>
13    </Router>
14  );
15}
16
17export default App;

Understanding React Router

React Router allows the react single page application to switch between views dynamically. Key components include:

1. BrowserRouter: Wraps the entire react app to enable routing.

2. Route Component: Defines paths for different web pages.

3. Switch: Ensures only one route is active at a time.

4. Route Exact Path: Ensures exact matching for routes.

With react router dom, the same page dynamically updates based on user actions, eliminating unnecessary page reloads.

Creating Components

Home Component

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1import React from "react";
2
3function Home() {
4  return <h1>Awesome Homepage Subtitle</h1>;
5}
6
7export default Home;

Contact Component

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1import React from "react";
2
3function Contact() {
4  return <h1>Contact Us</h1>;
5}
6
7export default Contact;

Now, when users click a desired link, they will see new content without the entire page refreshing.

The Role of export default in React

In React, the export default keyword allows a module to be imported easily. Examples include:

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1export default function Homepage() {
2  return <h1>Welcome to the Homepage</h1>;
3}

And in another file:

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1import Homepage from "./Homepage";

This simplifies the directory structure and improves code organization.

Handling API Calls in React SPA

A single page application SPA often fetches data from APIs without reloading the current web page. Example using fetch():

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1import React, { useState, useEffect } from "react";
2
3function UserProfile() {
4  const [user, setUser] = useState(null);
5
6  useEffect(() => {
7    fetch("https://api.example.com/user")
8      .then((response) => response.json())
9      .then((data) => setUser(data));
10  }, []);
11
12  if (!user) return <p>Loading...</p>;
13
14  return <h1>Awesome User Profile: {user.name}</h1>;
15}
16
17export default UserProfile;

Using React Testing Library

To test a react app, install react testing library:

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1npm install @testing-library/react

This helps test user interactions in a react SPA.

The Bottom Line!

A react single page application offers fast, efficient, and interactive experiences for users. By using react router dom, developers can structure their react project effectively, ensuring smooth navigation within a single page app.

If you’re building a new react project, install react router, use export default app, and leverage state management to enhance your web application. Whether you're creating a simple react app or a complex multi page application, React makes development easier with tools like react scripts and API handling.

Would you like a practical example of routing with React? 🚀