How can I recharge every change I make in my app, made with React Native?

I make changes to the code and even then it does not refresh anything on the cell phone when debugging the app.

import React, { Component } from 'react';
import { Platform, StyleSheet, Text, View } from 'react-native';

const instructions = Platform.select({
    ios: 'Press Cmd+R to reload,\n' + 'Cmd+D or shake for dev menu',
    android: 'Double tap R on your keyboard to reload,\n' +
        'Shake or press menu button for dev menu',
});

type Props = {};
export default class App extends Component < Props > {
    render() {
        return (

          <View style={styles.container}>
        <Text style={styles.welcome}>
          Welcome to React Native!
        </Text>
        <Text style={styles.instructions}>
          This is a React Native snapshot test.
        </Text>
      </View>

        );
    }
}

const styles = StyleSheet.create({
    container: {
        flex: 1,
        justifyContent: 'center',
        alignItems: 'center',
        backgroundColor: '#F5FCFF',
    },
    welcome: {
        fontSize: 20,
        textAlign: 'center',
        margin: 10,
    },
    instructions: {
        textAlign: 'center',
        color: '#333333',
        marginBottom: 5,
    },
});