Nomadic Functions
Where selfishness is good™
Here are the functions used in Robert Penners easing demo’s, converted to javascript.
JAVASCRIPT

Sine={

    'easeIn':function(t,b,c,d) { return-c*Math.cos(t/d*(Math.PI/2))+c+b; },
    'easeOut':function(t,b,c,d) { return c*Math.sin(t/d*(Math.PI/2))+b; },
    'easeInOut':function(t,b,c,d) { return-c/2*(Math.cos(Math.PI*t/d)-1)+b; }
};

Quint={

    'easeIn':function(t,b,c,d) { return c*(t/=d)*t*t*t*t+b; },
    'easeOut':function(t,b,c,d) { return c*((t=t/d-1)*t*t*t*t+1)+b; },
    'easeInOut':function(t,b,c,d) {
    
        if((t/=d/2)<1) return c/2*t*t*t*t*t+b;
        return c/2*((t-=2)*t*t*t*t+2)+b;
        
    }
};

Quart={

    'easeIn':function(t,b,c,d) { return c*(t/=d)*t*t*t+b; },
    'easeOut':function(t,b,c,d) { return-c*((t=t/d-1)*t*t*t-1)+b; },
    'easeInOut':function(t,b,c,d) {
    
        if((t/=d/2)<1) return c/2*t*t*t*t+b;
        return-c/2*((t-=2)*t*t*t-2)+b;

    }
};

Quad={

    'easeIn':function(t,b,c,d) { return c*(t/=d)*t+b; },
    'easeOut':function(t,b,c,d) { return-c*(t/=d)*(t-2)+b; },
    'easeInOut':function(t,b,c,d) {
    
        if((t/=d/2)<1) return c/2*t*t+b;
        return-c/2*((--t)*(t-2)-1)+b;
        
    }
};

Linear={

    'easeIn':function(t,b,c,d) { return c*t/d+b; },
    'easeOut':function(t,b,c,d) { return c*t/d+b; },
    'easeInOut':function(t,b,c,d) { return c*t/d+b; }
};

Expo={

    'easeIn':function(t,b,c,d) { return(t==0)?b:c*Math.pow(2, 10*(t/d-1))+b; },
    'easeOut':function(t,b,c,d) { return(t==d)?b+c:c*(-Math.pow(2,-10*t/d)+1)+b; },
    'easeInOut':function(t,b,c,d) {
    
        if(t==0) return b;
        if(t==d) return b+c;
        if((t/=d/2)<1) return c/2*Math.pow(2, 10*(t-1))+b;
        return c/2*(-Math.pow(2,-10*--t)+2)+b;
        
    }
};

Elastic={

    'easeIn':function(t,b,c,d,a,p) {
    
        if(t==0) return b; if((t/=d)==1) return b+c; if(!p) p=d*.3;
        if(!a || a<Math.abs(c)) { a=c; var s=p/4; }
        else var s=p/(2*Math.PI)*Math.asin(c/a);
        return-(a*Math.pow(2,10*(t-=1))*Math.sin((t*d-s)*(2*Math.PI)/p))+b;
        
    },
    'easeOut':function(t,b,c,d,a,p) {
    
        if(t==0) return b; if((t/=d)==1) return b+c; if(!p) p=d*.3;
        if(!a || a<Math.abs(c)) { a=c; var s=p/4; }
        else var s=p/(2*Math.PI)*Math.asin(c/a);
        return(a*Math.pow(2,-10*t)*Math.sin((t*d-s)*(2*Math.PI)/p)+c+b);
        
    },
    'easeInOut':function(t,b,c,d,a,p) {
    
        if(t==0) return b; if((t/=d/2)==2) return b+c; if(!p) p=d*(.3*1.5);
        if(!a || a<Math.abs(c)) { a=c; var s=p/4; }
        else var s=p/(2*Math.PI)*Math.asin(c/a);
        if(t<1) return-.5*(a*Math.pow(2,10*(t-=1))*Math.sin((t*d-s)*(2*Math.PI)/p))+b;
        return a*Math.pow(2,-10*(t-=1))*Math.sin((t*d-s)*(2*Math.PI)/p)*.5+c+b;
        
    }
};

Cubic={

    'easeIn':function(t,b,c,d) { return c*(t/=d)*t*t+b; },
    'easeOut':function(t,b,c,d) { return c*((t=t/d-1)*t*t+1)+b; },
    'easeInOut':function(t,b,c,d) {
    
        if((t/=d/2)<1) return c/2*t*t*t+b;
        return c/2*((t-=2)*t*t+2)+b;
    
    }
};

Circ={

    'easeIn':function(t,b,c,d) { return-c*(Math.sqrt(1-(t/=d)*t)-1)+b; },
    'easeOut':function(t,b,c,d) { return c*Math.sqrt(1-(t=t/d-1)*t)+b; },
    'easeInOut':function(t,b,c,d) {
    
        if((t/=d/2)<1) return-c/2*(Math.sqrt(1-t*t)-1)+b;
        return c/2*(Math.sqrt(1-(t-=2)*t)+1)+b;
        
    }
};

Bounce={

    'easeOut':function(t,b,c,d) {
    
        if((t/=d)<(1/2.75)) {
            return c*(7.5625*t*t)+b;
        } else if(t<(2/2.75)) {
            return c*(7.5625*(t-=(1.5/2.75))*t+.75)+b;
        } else if(t<(2.5/2.75)) {
            return c*(7.5625*(t-=(2.25/2.75))*t+.9375)+b;
        } else {
            return c*(7.5625*(t-=(2.625/2.75))*t+.984375)+b;
        }
    },
    'easeIn':function(t,b,c,d) { return c-Bounce.easeOut(d-t, 0, c, d)+b; },
    'easeInOut':function(t,b,c,d) {
    
        if(t<d/2) return Bounce.easeIn(t*2, 0, c, d)*.5+b;
        else return Bounce.easeOut(t*2-d, 0, c, d)*.5+c*.5+b;
        
    }
};

Back={

    'easeIn':function(t,b,c,d,s) {
    
        if(s==undefined) s=1.70158;
        return c*(t/=d)*t*((s+1)*t-s)+b;
        
    },
    'easeOut':function(t,b,c,d,s) {
    
        if(s==undefined) s=1.70158;
        return c*((t=t/d-1)*t*((s+1)*t+s)+1)+b;
        
    },
    'easeInOut':function(t,b,c,d,s) {
    
        if(s==undefined) s=1.70158; 
        if((t/=d/2)<1) return c/2*(t*t*(((s*=(1.525))+1)*t-s))+b;
        return c/2*((t-=2)*t*(((s*=(1.525))+1)*t+s)+2)+b;
        
    }
};
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