touch.js

//     Zepto.js
//     (c) 2010-2012 Thomas Fuchs
//     Zepto.js may be freely distributed under the MIT license.

;(function($){
  var touch = {}, touchTimeout

  function parentIfText(node){
    return 'tagName' in node ? node : node.parentNode
  }

  function swipeDirection(x1, x2, y1, y2){
    var xDelta = Math.abs(x1 - x2), yDelta = Math.abs(y1 - y2)
    return xDelta >= yDelta ? (x1 - x2 > 0 ? 'Left' : 'Right') : (y1 - y2 > 0 ? 'Up' : 'Down')
  }

  var longTapDelay = 750, longTapTimeout

  function longTap(){
    longTapTimeout = null
    if (touch.last) {
      touch.el.trigger('longTap')
      touch = {}
    }
  }

  function cancelLongTap(){
    if (longTapTimeout) clearTimeout(longTapTimeout)
    longTapTimeout = null
  }

  $(document).ready(function(){
    var now, delta

    $(document.body).bind('touchstart', function(e){
      now = Date.now()
      delta = now - (touch.last || now)
      touch.el = $(parentIfText(e.touches[0].target))
      touchTimeout && clearTimeout(touchTimeout)
      touch.x1 = e.touches[0].pageX
      touch.y1 = e.touches[0].pageY
      if (delta > 0 && delta <= 250) touch.isDoubleTap = true
      touch.last = now
      longTapTimeout = setTimeout(longTap, longTapDelay)
    }).bind('touchmove', function(e){
      cancelLongTap()
      touch.x2 = e.touches[0].pageX
      touch.y2 = e.touches[0].pageY
    }).bind('touchend', function(e){
       cancelLongTap()

      // double tap (tapped twice within 250ms)
      if (touch.isDoubleTap) {
        touch.el.trigger('doubleTap')
        touch = {}

      // swipe
      } else if ((touch.x2 && Math.abs(touch.x1 - touch.x2) > 30) ||
                 (touch.y2 && Math.abs(touch.y1 - touch.y2) > 30)) {
        touch.el.trigger('swipe') &&
          touch.el.trigger('swipe' + (swipeDirection(touch.x1, touch.x2, touch.y1, touch.y2)))
        touch = {}

      // normal tap
      } else if ('last' in touch) {
        touch.el.trigger('tap')

        touchTimeout = setTimeout(function(){
          touchTimeout = null
          touch.el.trigger('singleTap')
          touch = {}
        }, 250)
      }
    }).bind('touchcancel', function(){
      if (touchTimeout) clearTimeout(touchTimeout)
      if (longTapTimeout) clearTimeout(longTapTimeout)
      longTapTimeout = touchTimeout = null
      touch = {}
    })
  })

  ;['swipe', 'swipeLeft', 'swipeRight', 'swipeUp', 'swipeDown', 'doubleTap', 'tap', 'singleTap', 'longTap'].forEach(function(m){
    $.fn[m] = function(callback){ return this.bind(m, callback) }
  })
})(Zepto)