Laravel use package in package

I'm developing a package in Laravel 5.5 where I need this package:

http://ift.tt/1dvwKFA

The problem is that It's not registering for some reason. When I dd in the JavaScriptServiceProvider.php nothing happens. When I use the Javascript facade I get an error that it does not exists?!

My package composer.json file:

"require": {
        "php" : "^7.0",
        "illuminate/support": "~5.5.0",
        "laracasts/utilities": "^3.0"
    },

I use Laravel 5.5 so it should be registered by default (composer.json from laracasts package):

"extra": {
        "laravel": {
            "providers": [
                "Laracasts\\Utilities\\JavaScript\\JavaScriptServiceProvider"
            ],
            "aliases": {
                "JavaScript": "Laracasts\\Utilities\\JavaScript\\JavaScriptFacade"
            }
        }
    }

What am I doing wrong here?

via Chebli Mohamed