How to use inline easing with ScrollTo plug-in

Question

I try to use ScrollTo plug-in with some easing effect.

And I don't want to include easing plug-in file, because I will use only once and only one easing effect.

This 'easeOutBack' I want to use :

easeOutBack: function (x, t, b, c, d, s) {
        if (s == undefined) s = 1.70158;
        return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b;
}

And my scrollTo's function code like..

$(window).scrollTo(element,800,{offset:-80,onAfter:function(){
            alert('done');
}});

So I try to insert a easing effect like...

$(window).scrollTo(element,800,{offset:-80,
easing:function(x, t, b, c, d){
    return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
},
onAfter:function(){
    alert('done');
}});

It dosn't work.

TypeError: b.easing[this.easing] is not a function

Answer 1

You can simply store the easing function in $.easing:

$.easing.easeOutBack = function(x, t, b, c, d, s) {
    if(s == undefined) s = 1.70158;
    return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
};

After that you can use it just like you would do when the easing plugin is loaded.

Passing the function directly doesn't work because jQuery's animate() only accepts a string for the easing function (which is looked up in $.easing).