Create a UX bundle

Tip

Before reading this, you may want to have a look at :doc:`Best Practices for Reusable Bundles </bundles/best_practices>`.

Here are a few tricks to make your bundle install as a UX bundle.

composer.json file

Your composer.json file must have the symfony-ux keyword:

{
    "keywords": ["symfony-ux"]
}

Assets location

Your assets must be located in one of the following directories, with a package.json file so Flex can handle it during install/update:

• /assets (recommended)
• /Resources/assets
• /src/Resources/assets

package.json file

Your package.json file must contain a symfony config with controllers defined, and also add required packages to the peerDependencies:

{
    "name": "@acme/feature",
    "version": "1.0.0",
    "symfony": {
        "controllers": {
            "slug": {
                "main": "dist/controller.js",
                "fetch": "eager",
                "enabled": true,
                "autoimport": {
                    "@acme/feature/dist/bootstrap4-theme.css": false,
                    "@acme/feature/dist/bootstrap5-theme.css": true
                }
            }
        }
    },
    "peerDependencies": {
        "@hotwired/stimulus": "^3.0.0",
        "slugify": "^1.6.5"
    }
}

In this case, the file located at [assets directory]/dist/controller.js will be exposed.

Tip

You can either write raw JS in this dist/controller.js file, or you can e.g. write your controller with TypeScript and transpile it to JavaScript.

Here is an example to do so:

1. Add the following to your package.json file:

   {
       "scripts": {
           "build": "babel src --extensions .ts -d dist"
       },
       "devDependencies": {
           "@babel/cli": "^7.20.7",
           "@babel/core": "^7.20.12",
           "@babel/plugin-proposal-class-properties": "^7.18.6",
           "@babel/preset-env": "^7.20.2",
           "@babel/preset-typescript": "^7.18.6",
           "@hotwired/stimulus": "^3.2.1",
           "typescript": "^4.9.5"
       }
   }

2. Run npm install to install the new dependencies.

3. Write your Stimulus controller with TypeScript in src/controller.ts.

4. Run npm run build to transpile your TypeScript controller into JavaScript.

To use your controller in a template (e.g. one defined in your bundle) you can use it like this:

<div
    {{ stimulus_controller('acme/feature/slug', { modal: 'my-value' }) }}
    {#
        will render:
        data-controller="acme--feature--slug"
        data-acme--feature--slug-modal-value="my-value"
    #}
>
    ...
</div>

Don't forget to add symfony/stimulus-bundle:^2.9 as a composer dependency to use Twig stimulus_* functions.

Tip

Controller Naming: In this example, the name of the PHP package is acme/feature and the name of the controller in package.json is slug. So, the full controller name for Stimulus will be acme--feature--slug, though with the stimulus_controller() function, you can use acme/feature/slug.

Each controller has a number of options in package.json file:

Option	Description
enabled	Whether the controller should be enabled by default.
main	Path to the controller file.
fetch	How controller & dependencies are included when the page loads. Use eager (default) to make controller & dependencies included in the JavaScript that's downloaded when the page is loaded. Use lazy to make controller & dependencies isolated into a separate file and only downloaded asynchronously if (and when) the data-controller HTML appears on the page.
autoimport	List of files to be imported with the controller. Useful e.g. when there are several CSS styles depending on the frontend framework used (like Bootstrap 4 or 5, Tailwind CSS...). The value must be an object with files as keys, and a boolean as value for each file to set whether the file should be imported.