code: function PEhandler(ev) {
          var store = this.store;
          var removePointer = false;
  
          var eventTypeNormalized = ev.type.toLowerCase().replace('ms', '');
          var eventType = POINTER_INPUT_MAP[eventTypeNormalized];
          var pointerType = IE10_POINTER_TYPE_ENUM[ev.pointerType] || ev.pointerType;
  
          var isTouch = (pointerType == INPUT_TYPE_TOUCH);
  
          // get index of the event in the store
          var storeIndex = inArray(store, ev.pointerId, 'pointerId');
  
          // start and mouse must be down
          if (eventType & INPUT_START && (ev.button === 0 || isTouch)) {
              if (storeIndex < 0) {
                  store.push(ev);
                  storeIndex = store.length - 1;
              }
          } else if (eventType & (INPUT_END | INPUT_CANCEL)) {
              removePointer = true;
          }
  
          // it not found, so the pointer hasn't been down (so it's probably a hover)
          if (storeIndex < 0) {
              return;
          }
  
          // update the event in the store
          store[storeIndex] = ev;
  
          this.callback(this.manager, eventType, {
              pointers: store,
              changedPointers: [ev],
              pointerType: pointerType,
              srcEvent: ev
          });
  
          if (removePointer) {
              // remove from the store
              store.splice(storeIndex, 1);
          }
      }
docs: handle mouse events
  @param {Object} ev