A react on/off button component

toggle.js

class Toggle extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      isTToggleOn: true 
    };
    // binding the handleClick method
    this.handleClick = this.handleclick.bind(this);
  }  
  
  handleClick() {
    this.setState(state => ({
      isToggleOn: !state.isToggleOn
    }));
  }  
  
  render() {
    return(
      <button onClick={this.handleClick}>
        {this.state.isToggleOn ? 'ON' : 'OFF'}
      </button>
    );
  }
}  

ReactDOM.render(
  <Toggle />,
  document.getElementById('root')
);