onKeyup (event) {
    let hash = window.location.hash.replace('#', '');

    // If key ESC is pressed
    if (event.keyCode === 27) {
      if (this.activeElement && hash === this.activeElement.id) {
        window.location.hash = '!';
      } else {
        this.unsetActive();
      }

      if (this.lastActive) {
        return false;
      }

      // Unfocus
      this.removeFocus();
    }
  }
Keyup event triggered
@param  {Event} event Event that was triggered
@return {void}