react component parent and child states (jsx is an example, this is just showing how to update parent state)

index.js

class ParentComponent extends Component{
    state = {
        parentValue: ''
    }

    handleParentValueChange = (value) => {
        this.setState({parentValue: value});
    }

    render() {
         return (
            <div className="col-sm-9" >
                <ChildComponent handleParentValueChange={this.handleParentValueChange}/> 
            </div>
        )
    }
}

export class ChildComponent extends Component {
    state = {
        childValue: ''
    }

    handleChildChange = () => {
        var value = this.state.childValue;
        this.props.handleParentValueChange(value);            
    }

    render() {
        return (
            <div >
                <input onChange={this.handleChildChange} />
            </div>            
        );
    }
}