BindExample.js

class App extends React.Component {
  constructor() {
    super();
    this.state = {
     clicked: false
    }
  }
  doSomething() {
   this.setState({clicked: true})
   console.log("state of clicked is", this.state.clicked)
  }

  render() {
   return (
     <button onClick={this.doSomething.bind(this)}> click me </button>
   )
  }
 }