Penner easing equations as arrow functions

easing.js

// ease-in

const easeInQuad = (t, b, c, d) =>
  c*(t/=d)*t + b;

const easeInCubic = (t, b, c, d) =>
  c*(t/=d)*t*t + b;

const easeInQuart = (t, b, c, d) =>
  c*(t/=d)*t*t*t + b;

const easeInQuint = (t, b, c, d) =>
  c*(t/=d)*t*t*t*t + b;

const easeInSine = (t, b, c, d) =>
  -c * Math.cos(t/d * (Math.PI/2)) + c + b;

const easeInExpo = (t, b, c, d) =>
  t==0 ? b : c * Math.pow(2, 10 * (t/d - 1)) + b;

const easeInCirc = (t, b, c, d) =>
  -c * (Math.sqrt(1 - (t/=d)*t) - 1) + b;

const easeInElastic = (t, b, c, d) => {
  var s=1.70158;var p=0;var a=c;
  if (t==0) return b; if ((t/=d)==1) return b+c; if (!p) p=d*.3;
  if (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;
};

const easeInBack = (t, b, c, d, s) => {
  if (s == undefined) s = 1.70158;
  return c*(t/=d)*t*((s+1)*t - s) + b;
};


// ease-out

const easeOutQuad = (t, b, c, d) =>
  -c *(t/=d)*(t-2) + b;

const easeOutCubic = (t, b, c, d) =>
  c*((t=t/d-1)*t*t + 1) + b;

const easeOutQuart = (t, b, c, d) =>
  -c * ((t=t/d-1)*t*t*t - 1) + b;

const easeOutQuint = (t, b, c, d) =>
  c*((t=t/d-1)*t*t*t*t + 1) + b;

const easeOutSine = (t, b, c, d) =>
  c * Math.sin(t/d * (Math.PI/2)) + b;

const easeOutExpo = (t, b, c, d) =>
  t==d ? b+c : c * (-Math.pow(2, -10 * t/d) + 1) + b;

const easeOutCirc = (t, b, c, d) =>
  c * Math.sqrt(1 - (t=t/d-1)*t) + b;

const easeOutElastic = (t, b, c, d) => {
  var s=1.70158;var p=0;var a=c;
  if (t==0) return b; if ((t/=d)==1) return b+c; if (!p) p=d*.3;
  if (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;
};

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

const easeOutBounce = (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;
  }
};


// ease-in-out

const easeInOutQuad = (t, b, c, d) => {
  if ((t/=d/2) < 1) return c/2*t*t + b;
  return -c/2 * ((--t)*(t-2) - 1) + b;
};

const easeInOutCubic = (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;
};

const easeInOutQuart = (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;
};

const easeInOutQuint = (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;
};

const easeInOutSine = (t, b, c, d) =>
  -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;

const easeInOutExpo = (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;
};

const easeInOutCirc = (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;
};

const easeInOutElastic = (t, b, c, d) => {
  var s=1.70158;var p=0;var a=c;
  if (t==0) return b; if ((t/=d/2)==2) return b+c; if (!p) p=d*(.3*1.5);
  if (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;
};

const easeInOutBack = (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;
};

Simple example of easeOutElastic using requestAnimationFrame.