e.touches[0].clientX ๋ฅผ e.touches && e.touches[0].clientX ๋ก ๋ณ๊ฒฝ
e.touches[0].clientX || e.clientX;
↓
(e.touches && e.touches[0].clientX) || e.clientX;
stackoverflow.com/questions/38527202/mouse-and-touch-events-not-working-as-expected