Table of Content

• Understanding SPAs (Single Page Applications)

• The Server Challenge in SPAs

• The Solution: _redirects File

• Making Sense of the Magic

• Real-World Applications

So you built yourself a very cool app using Single Page Application, with tools like Create React App, Vite, or Angular. There's just one tiny problem - the server isn't always on the same page as your app.

Let's start with the basics. SPAs don't play by the same rules as those old, traditional websites. Instead of having a separate HTML page for every darn "page," SPAs rely on JavaScript wizardry to make it look like they have a thousand pages, all on one single HTML canvas.

In a single-page application (SPA) there is typically only one HTML page, and JavaScript handles the dynamic rendering of content as users navigate between different "pages" within the application. This means that the URL in the browser changes, but the entire page doesn't reload

• In a typical SPA, you have a single HTML file (usually named index.html) in your project.

• JavaScript is responsible for rendering different content based on the URL, making it look like users are navigating between multiple pages.

Traditional Multi-Page Application (MPA) Structure:

• Multiple HTML Pages:

  • In a traditional MPA, you have multiple HTML files, each representing a different page or view of your website. These HTML files can be named according to their content, such as home.html, about.html, and contact.html

Full Page Reloads:

• When a user clicks on a link or enters a new URL in the browser's address bar, the browser makes a new request to the server for the corresponding HTML file.

• This results in a full-page reload. The entire HTML document, along with all its assets (CSS, JavaScript, images, etc.), is fetched and replaces the current page.

A Whiff of Confusion:

Now, here's where the trouble begins. When you type in a specific URL, like https://yourdomain.com/some-page, servers expect to find a page with that exact name. But in SPA-land, it doesn't quite work that way. So, what's a server to do? It scratches its virtual head and thinks, "404 Error

Using _redirects File:

• To solve this problem, you create a _redirects file in your public folder. This file contains rules that tell the server how to handle different URLs, inside the file type put /* /index.html 200

• The rule /* /index.html 200 in the _redirects file is saying: "For any URL request (indicated by /*), respond by serving the index.html file, and return a 200 status code (indicating success)."

Why It Works:

• When the server receives a request for any URL, it follows the rules in the _redirects file. So, if someone directly accesses a URL within your SPA, the server sends them the index.html file, and the SPA's JavaScript then takes over to display the correct content based on the URL.

Key differences between Single Page Applications (SPAs) and traditional multi-page applications (MPAs):

1. Page Loading Approach:

• SPA: In SPAs, there's typically only one initial HTML page loaded from the server. All subsequent "page" transitions and content updates are handled dynamically by JavaScript without full page reloads. This results in faster, more fluid user experiences.

• MPA: In multi-page applications, each distinct page has its own separate HTML file. When users navigate between pages, the browser requests and loads a new HTML page from the server, resulting in full page reloads. This can be slower and less responsive compared to SPAs.

2. Server Interaction:

• SPA: SPAs rely heavily on client-side JavaScript to interact with web services and fetch data as needed. They often use AJAX or fetch requests to communicate with APIs and retrieve data without requiring the server to generate full HTML pages for each request.

• MPA: In multi-page applications, the server generates complete HTML pages for each distinct page. When users navigate, the server processes the request, creates a new HTML page, and sends it back to the client. This server-side rendering approach can consume more server resources

In summary, the _redirects file ensures that the server always serves the index.html file for any URL, allowing your SPA's client-side routing to work properly and preventing 404 errors for direct URL access.