I'm trying to animate some component. I Just want to change the size of the width of a View. I'm been looking the simplest way to make simple animations.I'm using the library "Animated".I can't make this work

I'm looking for some tutorials and it doesn't work.For some reason the code doesn't reconize the initial width of a "Animated.View" it is a variable declarated on the constructor just like this "animationwidth = new Animated.Value(11);".I dont know if the problem is in the declaration of the variable, in the style of the "Animated.View"or in the "animated.timing" function

```
import React, { Component } from 'react';
import {Animated,Text,Alert,View, Image, Button} from 'react-native';

export default class Game extends Component {
    constructor(props) {
        super(props);
        this.state = {
            opa: 1
        };
        animationwidth = new Animated.Value(11);

    }
    componentDidmount(){
        Animated.timing(this.animationwidth, {
            toValue: 300
        }).start()
    }

    render(){
        return(
            <View style={{flex:1,alignItems:'center',backgroundColor:'green',justifyContent:'center'}}>
                <Animated.View style={{ height:250, width:this.animationwidth ,backgroundColor:'blue'}}/>
            </View>
        )
    }
}

```