Q:

Black screen after modifying index.js

I am following a tutorial online to learn how to use React.
The instructor made me create a project called albums and modify the content of index.js, however I get a black screen on the ios simulator.
What I did (following the instructor's details):
1) Create a new project react-native init-albums
2) Enter the project directory with   cd albums
3) Run react-native run-ios 
4) I can see on the simulator screen what is inside the file App.js (The initial screen of - I assume - any new React Native project). 
Press Cmd+R to reload, Cmd+D or shake for dev menu etc.
5) Delete the content inside index.js and replace it with:
import React from "react";
import { AppRegistry, Text } from "react-native";

const App = () => {
 return <Text>Some Text</Text>;
};

AppRegistry.registerComponent("albums", () => App);

It should appear Some Text on the top left of the simulator BUT it does not. The screen is black.
What am I doing wrong?

A:

You need to define a background color for you application. You should also import View from react-native
import { AppRegistry, Text, View } from "react-native";

const App = () => {
 return (
   <View style={{backgroundColor: 'white', flex:1}}>
     <Text>Some Text</Text>
   </View>
  );
};

The reason that it is black is because the in the AppDelegate.m the rootView backgroundColor has been changed in version 0.58.0
In prior versions it was 
rootView.backgroundColor = [[UIColor alloc] initWithRed:1.0f green:1.0f blue:1.0f alpha:1];

It is now the following in 0.58.+
rootView.backgroundColor = [UIColor blackColor];

