hammerjs/src/pointerevent.js

A javascript library for multi-touch gestures

var PointerEvent = Hammer.PointerEvent = {
  /**
   * holds all pointers
   * @type {Object}
   */
  pointers: {},

  /**
   * get a list of pointers
   * @returns {Array}     touchlist
   */
  getTouchList: function getTouchList() {
    var touchlist = [];
    // we can use forEach since pointerEvents only is in IE10
    Utils.each(this.pointers, function(pointer){
      touchlist.push(pointer);
    });

    return touchlist;
  },

  /**
   * update the position of a pointer
   * @param   {String}   type             EVENT_END
   * @param   {Object}   pointerEvent
   */
  updatePointer: function updatePointer(type, pointerEvent) {
    if(type == EVENT_END) {
      delete this.pointers[pointerEvent.pointerId];
    }
    else {
      pointerEvent.identifier = pointerEvent.pointerId;
      this.pointers[pointerEvent.pointerId] = pointerEvent;
    }

    // it's save to use Object.keys, since pointerEvents are only in newer browsers
    return Object.keys(this.pointers).length;
  },

  /**
   * check if ev matches pointertype
   * @param   {String}        pointerType     POINTER_MOUSE
   * @param   {PointerEvent}  ev
   */
  matchType: function matchType(pointerType, ev) {
    if(!ev.pointerType) {
      return false;
    }

    var pt = ev.pointerType
      , types = {};

    types[POINTER_MOUSE] = (pt === POINTER_MOUSE);
    types[POINTER_TOUCH] = (pt === POINTER_TOUCH);
    types[POINTER_PEN] = (pt === POINTER_PEN);
    return types[pointerType];
  },


  /**
   * get events
   */
  getEvents: function getEvents() {
    return [
      'pointerdown MSPointerDown',
      'pointermove MSPointerMove',
      'pointerup pointercancel MSPointerUp MSPointerCancel'
    ];
  },

  /**
   * reset the list
   */
  reset: function resetList() {
    this.pointers = {};
  }
};