React Native slow boot up iOS

Question

Is it normal for a React Native app to use about 30 seconds to boot up and just show the splash screen before showing actual app content when testing on device or am I doing something wrong? Did test this with a clean app with just the "Welcome to React Native!" text. In the simulator the boot up time is just 1 second. Do I have to bundle or optimize the app to perform better on the device? Have anyone else had these crazy loading times?

Tested on iOS 10 and iPhone 5S.

Answer 1

I ran into similar problem. The clean app created with react-native init just closed after showing the splash screen for about 20sec.

I was running my laptop and the iOS device in the same WiFi network and the problem turned out to be the VPN client (Endpoint Security VPN) on my laptop that prevented the React Native app from reaching the development server properly.

It might be that the VPN client isn't blocking the requests to the development server entirely and iOS forces the app to close before the requests timeout.

As soon as I switched the iOS device to 4G the app lauched normally.