How to Display Coin Prices Dynamically with JavaScript and Ruby on Rails

Learn how to dynamically display coin prices after selecting their names in your Ruby on Rails application using JavaScript and AJAX.
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Dynamically Displaying Coin Prices After Selection in Ruby on Rails

In today's web development landscape, user interactivity plays a crucial role in delivering a seamless experience. If you are building a Ruby on Rails application where users can invest in cryptocurrencies, you might want to display the price of a coin as soon as its name is selected from a dropdown menu. In this post, we’ll address how to achieve this functionality using JavaScript and AJAX.

The Problem

You have a selection dropdown in your form where users can choose a coin. However, after selecting a coin name, how can you display its current price, which is stored in your database? This is a common question for developers working with dynamic forms in Rails applications.

Here’s a quick look at how your form looks:

[[See Video to Reveal this Text or Code Snippet]]

This simple form allows users to select a coin, but we need to implement additional features to fetch and display the price based on their selection.

The Solution

To achieve this, you’ll be leveraging AJAX (Asynchronous JavaScript and XML) functionality in conjunction with your Rails backend. The major steps involve capturing the user's selection and making an asynchronous request for the price of the specified coin. Here’s how you can do it step-by-step.

Step 1: Set Up the JavaScript Functionality

You will need to use JavaScript (or CoffeeScript, as mentioned in the original question). Here’s a rough idea of how to implement it:

Capture the Selection: Use jQuery to detect when a user selects a coin from the dropdown.

Make an AJAX Request: Send the selected coin name to your Rails backend to fetch the current price.

Here's the JavaScript code that you can add to your application:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Configure Your Rails Backend

Next, you need to set up a controller action in your Ruby on Rails application to handle the AJAX request. The basic idea is to query the database for the price of the selected coin and send it back to the frontend.

Here’s a sample method you can add in your controller:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Connect It All Together

After implementing the JavaScript functionality and the Rails controller action, make sure everything is wired correctly:

URL Routing: Ensure your routes file has a path that points to get_prices action.

Display the Price: Update your view to reflect the fetched price, possibly by updating the text field where the price will be displayed.

Conclusion

With the above steps, you can effectively display the price of a coin dynamically after the user makes a selection. This enhances the interactivity of your application and improves user experience. Make sure to test your implementation thoroughly to ensure that the prices are displaying correctly upon selection.

By integrating JavaScript with Ruby on Rails, you open up a world of possibilities for interactive web applications, so keep exploring and enhancing your coding skills!