bind.js

"use strict"
class ErrorBox {
    constructor(div, gate) {
        this.div = div;
        console.log(div); //Output some instance 
        gate.addEventListener(this.gateListener);
    }

    gateListener(e) {
        console.log(this.div); //Output undefined
    }
}

class Gate {
    constructor() {
        this.handlers = [];
    }
    addEventListener(handler) {
        this.handlers.push(handler);
    }
    raise() {
        for (let handler of this.handlers) {
            handler();
        }
    }
}
let gate = new Gate();
let errorBox = new ErrorBox({}, gate);
gate.raise();