How to increase or decrease the time of the splash screen/launch screen of the react native ios?

Question

I am working with react native. In my project I used splash screen for both Android and iOS. On Android I increased the time of the splash screen in android/app/src/main/java/splashActivity.java as sleep(5000). Similarly, I want to increase or decrease the time of the splash screen on iOS. I don't know how to do it.