Child Contructor Binding

ChildConstructor.js

class ChildComponent extends React.Component {

  constructor(props) {
    super(props);
    this.state = { message: 'I am Child ' };
    this.printChild = this.printChild.bind(this);
  }
  render() {
    return <div>
      <p> Child Component</p>
      <input type="button" value="Print From Child" onClick={this.printChild} />
    </div>
  }

  printChild() {
    console.log(this.state.message)
    this.props.printParent( "Mars")
  }
}