React Simple Animation

ExandAnimation.js

import React from 'react';
import {
    StyleSheet,
    Text,
    View,
    TouchableOpacity,
    Animated,
    Easing
} from 'react-native';

export default class App extends React.Component {

    constructor(props) {
        super(props);
        this.animatedValue = new Animated.Value(25);
    }
    
    _animate = () => {
        Animated.timing(this.animatedValue, {
            toValue: 100,
            duration: 1000,
            easing: Easing.bounce
        }).start();
    };

    render() {
        const animatedStyle = {height: this.animatedValue};
        return (
            <View>
                <TouchableOpacity style={styles.container} onPress={this._animate}>
                    <Animated.View style={[styles.box, animatedStyle]}>
                        <Text style={styles.text}>Facebook Login</Text>
                    </Animated.View>
                </TouchableOpacity>
            </View>
        )
    }
}

const styles = StyleSheet.create({
    container: {
    },
    box: {
        backgroundColor: '#33a1d1',
        width: 100,
        height: 25
    },
    text: {
        color: '#fff'
    }

});