Passing in url params on app startup

I am having a tough time getting the url params when the app starts up. The use case is that I need to create a QR code that has the basic url plus an event code so that when the app starts I can load the correct data set for that event. I have tried to capture it using JavaScript but what I learned is that the ‘page’ that is first loaded is not your startup page, and when Ionic changes pages, it does not carry forward the url params so they get lost along the way.

What do you suggest to solve my problem?