Revert some of the non-essential changes of #630 (for ease of merging other branches) (#652)

packages/rrweb/src/record/observer.ts

@@ -194,9 +194,8 @@ function initMoveObserver(
     },
     callbackThreshold,
   );
-
+  const updatePosition = throttle<MouseEvent | TouchEvent | DragEvent>(
-  // update position for mouse, touch, and drag events (drag event extends mouse event)
+    (evt) => {
-  function handleUpdatePositionEvent(evt: MouseEvent | TouchEvent) {
       const target = getEventTarget(evt);
       const { clientX, clientY } = isTouchEvent(evt)
         ? evt.changedTouches[0]
@@ -210,29 +209,10 @@ function initMoveObserver(
         id: mirror.getId(target as INode),
         timeOffset: Date.now() - timeBaseline,
       });
-  }
+      // it is possible DragEvent is undefined even on devices
-
+      // that support event 'drag'
-  // separate call for non-drag events, in case DragEvent is not defined
-  const updatePosition = throttle<MouseEvent | TouchEvent>(
-    (evt) => {
-      handleUpdatePositionEvent(evt);
       wrappedCb(
-        evt instanceof MouseEvent
+        typeof DragEvent !== 'undefined' && evt instanceof DragEvent
-          ? IncrementalSource.MouseMove
-          : IncrementalSource.TouchMove,
-      );
-    },
-    threshold,
-    {
-      trailing: false,
-    },
-  );
-  // call for drag events, when DragEvent is defined
-  const updateDragPosition = throttle<MouseEvent | TouchEvent | DragEvent>(
-    (evt) => {
-      handleUpdatePositionEvent(evt);
-      wrappedCb(
-        evt instanceof DragEvent
           ? IncrementalSource.Drag
           : evt instanceof MouseEvent
           ? IncrementalSource.MouseMove
@@ -244,13 +224,10 @@ function initMoveObserver(
       trailing: false,
     },
   );
-  // it is possible DragEvent is undefined even on devices
-  // that support event 'drag'
-  const dragEventDefined = typeof DragEvent !== 'undefined';
   const handlers = [
     on('mousemove', updatePosition, doc),
     on('touchmove', updatePosition, doc),
-    on('drag', dragEventDefined ? updateDragPosition : updatePosition, doc),
+    on('drag', updatePosition, doc),
   ];
   return () => {
     handlers.forEach((h) => h());