javascript - Change state in forEach loop

How can I change state on click event on the buttons? Now I have error

Uncaught TypeError: this.setState is not a function

I know that I can't use here this.setState but I can't understand where should I make bind

class Popup extends React.Component {
  constructor(props){
    super(props);
    this.state = {opened: false};
  }

  componentDidMount(){
    var popupOpenBtn = document.querySelectorAll('[data-popup]');

    popupOpenBtn.forEach(function(item) {

      item.addEventListener("click", function(){
        this.setState({
          opened: true
        });
      })
    });
  }