Binding touch events and moving an element

Question

I have the following jQuery plugin that binds touch events and moves an element.

In the functions moveMe and snap, there is duplicate code doing the same thing because I couldn't figure out how to refactor the scope of the functions to only do this once.

$.fn.draggable = function(limit) {
 var offset = null; 
 var start = function(e) { 
 var orig = e.originalEvent; 
 var pos = $(this).position(); 
 offset = { 
 x: orig.changedTouches[0].pageX - pos.left, 
 //y: orig.changedTouches[0].pageX - pos.top 
 };
 $(this).stop(true,false);
 }; 
 var moveMe = function(e) { 
 e.preventDefault(); 
 $('body').css('overflow-x','hidden');
 var orig = e.originalEvent;
 var touchX = orig.changedTouches[0].pageX;
 var difference = touchX - offset.x;
 var move;
 if (difference >= limit) {
 move = limit;
 } else if (difference <= 0) {
 move = 0;
 } else {
 move = difference;
 }
 $(this).css({ 
 left: move,
 //left: orig.changedTouches[0].pageX - offset.x 
 });
 };
 var snap = function(e) {
 var orig = e.originalEvent;
 var touchX = orig.changedTouches[0].pageX;
 var difference = touchX - offset.x;
 var threshold = limit*0.75;
 if (difference >= limit) {
 move = limit;
 } else if (difference <= 0) {
 move = 0;
 } else {
 move = difference;
 }
 if (threshold > (limit-move)) {
 $(this).animate({
 left : limit
 });
 } else {
 $(this).animate({
 left : 0
 });
 }
 };
 this.bind("touchstart", start); 
 this.bind("touchmove", moveMe); 
 this.bind("touchend", snap);
};
$("#container").draggable(200);

Answer 1

Could you write something like this?

var limited = function( value, limit ){
 if (value >= limit) { 
 return limit; 
 } else if (value <= 0) { 
 return 0; 
 } else { 
 return value; 
 } 
}

then, when you need to work out move, just write move = limited( difference, limit );