text: var addListenerToElement = function (element, type, callback, r) {
    // 暂时忽略capture
    element.addEventListener(type, callback, {
      passive: false
    })
  }
  
  export default {
    methods: {
      touchtrack: function (element, method, useCancel) {
        var self = this
        var x0 = 0
        var y0 = 0
        var x1 = 0
        var y1 = 0
        var fn = function ($event, state, x, y) {
          if (self[method]({
            target: $event.target,
            currentTarget: $event.currentTarget,
            preventDefault: $event.preventDefault.bind($event),
            stopPropagation: $event.stopPropagation.bind($event),
            touches: $event.touches,
            changedTouches: $event.changedTouches,
            detail: {
              state,
              x0: x,
              y0: y,
              dx: x - x0,
              dy: y - y0,
              ddx: x - x1,
              ddy: y - y1,
              timeStamp: $event.timeStamp
            }
          }) === false) {
            return false
          }
        }
  
        var $eventOld = null
        addListenerToElement(element, 'touchstart', function ($event) {
          if ($event.touches.length === 1 && !$eventOld) {
            $eventOld = $event
            x0 = x1 = $event.touches[0].pageX
            y0 = y1 = $event.touches[0].pageY
            return fn($event, 'start', x0, y0)
          }
        })
        addListenerToElement(element, 'touchmove', function ($event) {
          if ($event.touches.length === 1 && $eventOld) {
            var res = fn($event, 'move', $event.touches[0].pageX, $event.touches[0].pageY)
            x1 = $event.touches[0].pageX
            y1 = $event.touches[0].pageY
            $event.preventDefault()
            return res
          }
        })
        addListenerToElement(element, 'touchend', function ($event) {
          if ($event.touches.length === 0 && $eventOld) {
            $eventOld = null
            return fn($event, 'end', $event.changedTouches[0].pageX, $event.changedTouches[0].pageY)
          }
        })
        addListenerToElement(element, 'touchcancel', function ($event) {
          if ($eventOld) {
            var $eventTemp = $eventOld
            $eventOld = null
            return fn($event, useCancel ? 'cancel' : 'end', $eventTemp.touches[0].pageX, $eventTemp.touches[0].pageY)
          }
        })
      }
    }
  }
  