Part 3 - Adding listeners for touch events

Post.js

addListeners = () => {
  window.addEventListener('scroll', this.onScroll);
  window.addEventListener('touchstart', this.onTouchStart);
  window.addEventListener('touchend', this.onTouchEnd);
};

removeListeners = () => {
  window.removeEventListener('scroll', this.onScroll);
  window.removeEventListener('touchend', this.onTouchEnd);
  window.removeEventListener('touchstart', this.onTouchStart);
};

onTouchStart = () => (this.isTouching = true);

onTouchEnd = () => (this.isTouching = false);