App.js

export default class App extends Component<{}> {
    sayHi() {
        console.log("Hello!") // breakpoint on this line
    }

    render() {
        return (
            <View style={styles.container}>
                <Text style={styles.welcome}>
                    Welcome to React Native!
                </Text>
                <Text style={styles.instructions}>
                    To get started, edit App.js
                </Text>
                <Text style={styles.instructions}>
                    {instructions}
                </Text>
                <Button onPress={this.sayHi} title="Click me"/>
            </View>
        );
    }
}