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Express req.xhr Property

Updated on Nov 24, 2024
By Mari Selvan
👁️ 38 - Views
⏳ 4 mins
💬 1 Comment
Express req.xhr Property

Photo Credit to CodeToFun

🙋 Introduction

In web development, distinguishing between regular HTTP requests and AJAX (Asynchronous JavaScript and XML) requests is crucial for delivering a seamless user experience.

Express.js provides the req.xhr property, allowing you to identify AJAX requests within your route handlers and middleware functions.

This guide will delve into the syntax, usage, and practical examples of the req.xhr property in Express.js.

💡 Syntax

The syntax for using the req.xhr property is simple:

syntax.js
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if (req.xhr) {
  // Code to handle AJAX request
} else {
  // Code to handle regular HTTP request
}

❓ How req.xhr Works

The req.xhr property in Express.js is a boolean value that indicates whether the request was made with XMLHttpRequest (commonly used in AJAX requests). When req.xhr is true, it signifies an AJAX request, and when false, it denotes a regular HTTP request.

example.js
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app.get('/api/data', (req, res) => {
  if (req.xhr) {
    // Respond to AJAX request
    res.json({ data: 'AJAX response' });
  } else {
    // Respond to regular HTTP request
    res.send('Regular HTTP response');
  }
});

In this example, the route /api/data checks req.xhr to differentiate between an AJAX request and a regular HTTP request, responding accordingly.

📚 Use Cases

  1. Dynamic Content Loading:

    Utilize req.xhr to load partial content for AJAX requests, enhancing the user experience with dynamic updates.

    example.js
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    app.get('/dynamic-content', (req, res) => {
      if (req.xhr) {
        // Load partial content for AJAX requests
        res.render('partials/dynamic-content');
      } else {
        // Render full page for regular HTTP requests
        res.render('full-page');
      }
    });
  2. Conditional Responses:

    Customize responses based on the request type using req.xhr, providing different formats for AJAX and regular requests.

    example.js
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    app.get('/api/user/:id', (req, res) => {
      const userId = req.params.id;
      const userData = getUserData(userId);
    
      if (req.xhr) {
        // Respond with JSON for AJAX requests
        res.json(userData);
      } else {
        // Render user profile page for regular HTTP requests
        res.render('user-profile', { userData });
      }
    });

🏆 Best Practices

  1. Consistent API Responses:

    Ensure consistency in API responses by using req.xhr to format JSON responses for AJAX requests.

    example.js
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    app.get('/api/data', (req, res) => {
      if (req.xhr) {
        // Consistent JSON response for AJAX requests
        res.json({ data: 'AJAX response' });
      } else {
        // Handle non-AJAX requests as needed
        res.send('Regular HTTP response');
      }
    });
  2. Graceful Degradation:

    Implement graceful degradation by providing fallbacks for non-AJAX scenarios, ensuring a functional user experience in all situations.

    example.js
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    app.get('/fallback', (req, res) => {
      if (req.xhr) {
        // Provide AJAX-specific content
        res.json({ message: 'AJAX response' });
      } else {
        // Fallback for non-AJAX requests
        res.send('Fallback content for regular HTTP request');
      }
    });

🎉 Conclusion

The req.xhr property in Express.js is a valuable tool for identifying AJAX requests and tailoring your server's responses accordingly. By understanding how to use req.xhr effectively, you can enhance your Express.js applications with dynamic and responsive behavior.

Now, equipped with knowledge about req.xhr, go ahead and implement AJAX-aware features in your Express.js projects!

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Author

author
👋 Hey, I'm Mari Selvan

For over eight years, I worked as a full-stack web developer. Now, I have chosen my profession as a full-time blogger at codetofun.com.

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Mari Selvan
Mari Selvan
9 months ago

If you have any doubts regarding this article (Express req.xhr Property), please comment here. I will help you immediately.

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