Hi Vincent,
if I remember correctly you should place custom code in the entry.js file. I can’t say if this will work for OneSignal though.
regards, Fabian
Hi Vincent, you can customize the phonegap build by downloading the phonegap package and changing the config.xml. i.e. add the onesignal plugin. After that you need to rebuild your app, see https://docs.mendix.com/refguide/customizing-phonegap-build-packages
I dont have experience with onesignal, but you might initialize it with a HTML/javascript widget, and add this snippet to the phone layout in your project. This is how it's done with the default Mendix push connector using FCM.
Whats the main reason for you to use onesignal over the default?