componentWillMount function in React Native Navigation - firebase

Question

I am new in Ract Native and I am trying to build a small app using react native navigation.
I can see in the movie-app example provided on their site (react native navigation) that they do not use a componentWillMount function in app.js, but they have a startApp() function instead, called in the constructor.
I am basically trying to define the firebase configuration in the componentWillMounth function, but a simple console log shows that the function is somehow never run.
I would like to set up the app properly, for best performance, so I am wondering if using the startApp function is basically the same, no need to use a componentWillMount function?
Update: Code below
index.ios.js
import App from './src/app';
const app = new App();
app.js
import ...
class App extends Component {
state = {
loggedIn: null
}
constructor(props) {
super(props);
this.startApp();
}
componentWillMount() {
console.log('COMPONENT WILL MOUNT');
// Initialize Firebase
const config = {
...
...
};
firebase.initializeApp(config);
}
startApp() {
console.log('START APP');
// Initialize Firebase here???
const tabs = [
...
];
if (this.state.loggedIn) {
Navigation.startTabBasedApp({
tabs,
tabsStyle: {
...
}
});
} else {
Navigation.startSingleScreenApp({
...
});
}
} // startApp
}
export default App;

Answer 1

Your componentWillMount is not being executed because you are not using your component within the React render lifecycle (you are instantiating it not in a render, but with new, which will only run the constructor of the component. Move it to your index render method, like this:
class EntryPoint extends React.Component {
render(){
<App />
}
}
AppRegistry.registerComponent('MyApp', ()=>EntryPoint);