This Symfony Bundle is useful if you need to expose constants to front.

composer require constant-exposure/constant-exposure-bundle:^2.2

In config/bundles.php, add this line:

return [
    ...
    ConstantExposureBundle\ConstantExposureBundle::class => ['all' => true],
];

Create a file config/packages/constant_exposure.yaml in your project. Then, configure constants to expose.

constant_exposure:
    parameter:
        debug: '%kernel.debug%'
        sentry_dsn: '%env(SENTRY_DSN)%'
        password_expire: !php/const App\Entity\Password::EXPIRE_PASSWORD 

Add this line in your Twig template. Pass as parameter a name for your JavaScript object.

{{ constant_exposure_object('ConstantExposure') }}

Get them in Javascript:

ConstantExposure.getParameter(PARAMETER_NAME [, DEFAUlT_VALUE = null] );

// Check if you are in debug mode
const isDebug = ConstantExposure.getParameter('debug');

// If sentry_dsn is not defined, default value is an empty string
const sentryDsn = ConstantExopsure.getParameter('sentry_dsn', '');

If you need to expose your constants on a route, add these lines in your routing file:

constant_exposure:
    resource: "@ConstantExposureBundle/Resources/config/routing.yaml"

Then, you can access it with this url:

• /constant-exposure.json for a JSON format
• /constant-exposure.xml for a XML format
• /constant-exposure.csv for a CSV format