Refactored files.

src/util.ts

@@ -1,3 +1,27 @@
 export function minmax(number: number, min: number, max: number) {
   return Math.min(max, Math.max(min, number));
 }
+
+export function isTouchEvent(event: Event): event is TouchEvent {
+  return "touches" in event;
+}
+
+export function isLeftMouseButton(buttonsValue: number) {
+  return buttonsValue === 1;
+}
+
+export function extractEventCoordinates(event: MouseEvent | TouchEvent): {
+  clientX: number;
+  clientY: number;
+} {
+  if (isTouchEvent(event)) {
+    return {
+      clientX: event.touches[0].clientX,
+      clientY: event.touches[0].clientY,
+    };
+  }
+  return {
+    clientX: event.clientX,
+    clientY: event.clientY,
+  };
+}