showRipple(e) {
    const rippleContainer = e.currentTarget;
    const size = rippleContainer.offsetWidth;
    const pos = rippleContainer.getBoundingClientRect();
    const x = e.pageX - pos.x - (size / 2);
    const y = e.pageY - pos.y - (size / 2);
    const style = 'top:' + y + 'px; left: ' + x + 'px; height: ' + size + 'px; width: ' + size + 'px;';
    const rippler = document.createElement('span');
    rippleContainer.appendChild(rippler);
    return rippler.setAttribute('style', style);
  }