React - State and props example

index.js

import React from "react";
import ReactDOM from "react-dom";

class Clicky extends React.Component {
  constructor(props) {
    super(props);

    this.state = {clickCount: 0};

    this.handleClick = this.handleClick.bind(this);
  }

  handleClick() {
    this.setState( prevState => ({
      clickCount: prevState.clickCount + 1
    }));
    console.log('clicked');
  }

  render() {
    return(
      <div>
        <h1>{this.state.clickCount} times clicked</h1>
        <button onClick={this.handleClick}>My name is {this.props.name} click me I love to be clicked</button>
      </div>
    );
  }
}

ReactDOM.render(
  <div>
    <Clicky name="Click Jnr"/>
  </div>,
  document.getElementById("root")
);