Detect mouse real direction

Question

My goal is to detect the direction of the last mouse movement before the mouseup event trigger.

To avoid validating small involuntary movements (ex: I go with the mouse to the right for 100px and then I stop but involuntarily do 2px to the left) I would confirm the direction only after the mouse pointer has achieved a minimum safety distance (gap) from the last point where it has reversed its direction.

Here is a simplification of my implementation:

var direction = "",
oldx = 0,
invert = 0,
gap = 10,
move = "",
mousemovemethod = function (e) {

    if (e.pageX < oldx) {
        if(direction == "right") invert = e.pageX;
        direction = "left";
        if(e.pageX < invert - gap) move = "left";
    } else if (e.pageX > oldx) {
        if(direction == "left") invert = e.pageX;
        direction = "right"
        if(e.pageX > invert + gap) move = "right";
    }

    document.body.innerHTML = "moving " + direction + ", last inversion point: " + invert + ", Validated movement: " + move;

    oldx = e.pageX;

}

document.addEventListener('mousemove', mousemovemethod);

And here is a fiddle

The code works but it seems to me verbose and unclear. I have always been poor in this kind of implementation and I was wondering if anyone knew a more elegant way of handling this mechanics.

Every suggestion is welcome.

Answer 1

function smooth(){
    var direction="",
    oldx = 0,
    noise=10,
    dir=0;
    mousemove=function(e){
       dir=oldx-e.pageX;
       if(Math.abs(dir)> noise){
          (dir <=0 )?direction="right":direction="left";
          oldx=e.pageX;
       }
       document.body.innerHTML = "moving " + direction;
   };
   document.addEventListener('mousemove', mousemove);
}

How about this?