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Extending Storefront with JavaScript

Spree Storefront can be easily extended with custom JavaScript. Most of the JavaScript in the storefront is powered by a framework called Stimulus.js which is the Ruby on Rails default. It’s a very simple and minimalistic framework only enhancing our server-side rendered HTML with a bit of interactivity.

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3rd party JavaScript libraries

Spree Storefront comes with a few 3rd party JavaScript libraries already included. Main libraries we’re using: You can find them in the app/assets/javascripts/vendor directory.

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Managing JavaScript dependencies

You’re probably wondering why these libraries are in the vendor directory, and not in node_modules. That’s because we’re not using Node.js at all. So no Yarn or npm. We’re using a different approach to manage dependencies. We’re using a tool called Importmaps to manage dependencies which is the Ruby on Rails default.
If you want to use a different JavaScript package manager you can do so by using jsbundling-rails gem.

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Install dependencies

To install dependencies you need to run the following command: 
bin/rails importmap pin react
This will install the dependencies, download the files to your vendor/javascript directory and add them to your config/importmap.rb file, eg. 
pin "react" # @19.1.0
Now you can just import the library in your application entry point, eg. application.js: 
import "react";

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Application entry point

Mentioned above, the application entry point is the application.js file. It’s located in the app/javascript directory. If you want to add custom JavaScript to your Spree storefront, you can do so by adding a new file to the app/javascript directory.

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Stimulus Controllers

Stimulus controllers are a way to add interactivity to your Spree storefront. Storefront controllers can be found in the Spree repository in the storefront/app/javascript/spree/storefront/controllers directory. You can find more information about Stimulus controllers in the Stimulus.js documentation. To add a new controller you need to create a new file in the app/javascript/controllers directory. It will be automatically picked up by the application. 
// app/javascript/controllers/hello_controller.js
import { Controller } from '@hotwired/stimulus'

export default class extends Controller {
  connect() {
    console.log("Hello Spree Commerce Stimulus!", this.element);
  }
}
To use the controller in your HTML you need to add the data-controller attribute to your element, eg. 
<div data-controller="hello">
  Hello Spree Commerce Stimulus!
</div>

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JavaScript snippets

If you need to add a small piece of JavaScript code (eg. tracking, marketing, analytics, customer service etc.) you can do this by:
  1. Declaring a new head partial in the config/initializers/spree.rb file, eg. 
    Rails.application.config.spree_storefront.head_partials << 'spree/shared/my_tracking_code'
  2. Creating a new file in the app/views/spree/shared/my_tracking_code.html.erb, where you can add your tracking code, eg. 
    <script>
  console.log("I'm a spy!");
</script>
With Spree 5.1 we’re going to release a new integrations feature which will allow you to easily connect your storefront to third party services, eg. Google Analytics, Facebook Pixel, etc.