Misleading argument in the example

[Alexandre887]

Introduction to browser events

Code:

  class Menu {
    handleEvent(event) {
      let method = 'on' + event.type[0].toUpperCase() + event.type.slice(1);
      this[method](event); // <=====
    }

    onMousedown() {
      elem.innerHTML = "Mouse button pressed";
    }

    onMouseup() {
      elem.innerHTML += "...and released.";
    }
  }

  let menu = new Menu();
  elem.addEventListener('mousedown', menu);
  elem.addEventListener('mouseup', menu);

There is no need to pass the event argument in the expression this[method](event), because the passed argument is not used in further code. This may mislead the reader.