How to define event handler as elements class method?

Question

I tried to define click event handler as elements class method

Why it is not working?

class Component extends HTMLElement {
    ...
    onclick () {
      console.log(event)
    }
}

But it works in this way

class Component extends HTMLElement {
    constructor() {
        super()
        this.onclick = console.log
    }

}

Answer 1

ES7+ way

class CustomElement extends HTMLElement {
    onclick = () => {...}
}