how-shall-i-maintain-referential-equality.jsx

class Dashboard extends Component {
  constructor(props) {
    super(props)
    
    // bind? slows down the initialization path, looks awful
    // when you have 20 of them (I have seen your code, I know)
    // and it increases bundle size
    this.handleStuff = this.handleStuff.bind(this)

    // _this is ugly.
    var _this = this
    this.handleStuff = function() {
      _this.setState({})
    }
    
    // If you can use an ES class then you can probably use an arrow
    // function (babel, or a modern browser). This isn't too bad but
    // putting all of your handlers in the constructor is kind of
    // not awesome
    this.handleStuff = () => {
      this.setState({})
    }
  }
  
  // this is nice, but it isn't JavaScript, not yet anyway, so now
  // we need to talk about how TC39 works and evaluate our draft
  // stage risk tolerance
  handleStuff = () => {}
}

The last pattern looks the cleans so what do you mean by is not Javascript yet?