class Parent extends Component {
  constructor() {
    this.state = {
      value: ''
    };
  }

  //...

  handleChangeValue = e => this.setState({value: e.target.value});

  //...

  render() {
    return (
      
    );
  }
}

class Child extends Component {
  //...

  render() {
    return (
      
    );
  }
}