class GODListener {
constructor() {
this.counter = 0;
}
handleClick() {
this.counter += 1;
console.log(this.counter);
}
}
const element = document.getElementById('testBtn');
const listener = new GODListener();
element.addEventListener("click", listener.handleClick);
<button id='testBtn'>Тест</button>
this.handleClick = this.handleClick.bind(this)или 2) стрелочная функцияhandleClick = () => { code }. Пример https://jsfiddle.net/0x13hwft/