App.js

import React, { Component } from 'react';
import Alice from './Alice';

class App extends Component {

  constructor() {
    super();
    this.state = {
      greeting: "Hello World!",
      parentMessage: "Hello Alice!"
    }

    setTimeout(() => {
      this.setState({greeting : "Hello World Updated!"})
    }, 10000)
  }

  render() {
    return (
      <div className="greeting">
        <h1> {this.state.greeting} </h1>
        <Alice newMsg={this.state.parentMessage} />
      </div>
    );
  }
}
export default App;