Parent Child

Parent.js

class Parent extends React.Component {

  constructor(props) {
    super(props);
    this.state = { message: 'I am parent ' };
    this.printParent = this.printParent.bind(this);
  }

  render() {
    return <div>
      <p>Parent Component</p>
      <ChildComponent printParent={this.printParent} />
    </div>
  }

  printParent() {
    console.log(this.state.message);
  }
}

ParentChild.js

class ChildComponent extends React.Component {

  render() {
    return <div>
      <p> Child Component</p>
      <input type="button" value="Print From Child" onClick={this.props.printParent} />
    </div>
  }
}