Easingの関数(JavaScript)や変数(Scss)をまとめました

class Easing {
  linear(t, b, c, d){
    return c * t / d + b;
  }
  jswing(t, b, c, d){
    return c * (0.5 - Math.cos(t / d * Math.PI) / 2) + b;
  }
  swing(t, b, c, d) {
    return -c *(t/=d)*(t-2) + b;
  }

  // ease in
  easeInQuad(t, b, c, d) {
    return c*(t/=d)*t + b;
  }
  easeInOutQuad(t, b, c, d) {
    if ((t/=d/2) < 1) return c/2*t*t + b;
    return -c/2 * ((--t)*(t-2) - 1) + b;
  }
  easeInCubic(t, b, c, d) {
    return c*(t/=d)*t*t + b;
  }
  easeInQuart(t, b, c, d) {
    return c*(t/=d)*t*t*t + b;
  }
  easeInQuint(t, b, c, d) {
    return c*(t/=d)*t*t*t*t + b;
  }
  easeInSine(t, b, c, d) {
    return -c * Math.cos(t/d * (Math.PI/2)) + c + b;
  }
  easeInExpo(t, b, c, d) {
    return (t==0) ? b : c * Math.pow(2, 10 * (t/d - 1)) + b;
  }
  easeInCirc(t, b, c, d) {
    return -c * (Math.sqrt(1 - (t/=d)*t) - 1) + b;
  }
  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;
  }
  easeInBack(t, b, c, d, s) {
    if (s == undefined) s = 1.70158;
    return c*(t/=d)*t*((s+1)*t - s) + b;
  }
  easeInBounce(t, b, c, d) {
    return c - easingFuncs.easeOutBounce (d-t, 0, c, d) + b;
  }

  // ease out
  easeOutQuad(t, b, c, d) {
    return -c *(t/=d)*(t-2) + b;
  }
  easeOutCubic(t, b, c, d) {
    return c*((t=t/d-1)*t*t + 1) + b;
  }
  easeOutQuart(t, b, c, d) {
    return -c * ((t=t/d-1)*t*t*t - 1) + b;
  }
  easeOutQuint(t, b, c, d) {
    return c*((t=t/d-1)*t*t*t*t + 1) + b;
  }
  easeOutSine(t, b, c, d) {
    return c * Math.sin(t/d * (Math.PI/2)) + b;
  }
  easeOutExpo(t, b, c, d) {
    return (t==d) ? b+c : c * (-Math.pow(2, -10 * t/d) + 1) + b;
  }
  easeOutCirc(t, b, c, d) {
    return c * Math.sqrt(1 - (t=t/d-1)*t) + b;
  }
  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;
  }
  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;
  }
  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
  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;
  }
  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;
  }
  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;
  }
  easeInOutSine(t, b, c, d) {
    return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
  }
  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;
  }
  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;
  }
  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;
  }
  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;
  }
  easeInOutBounce(t, b, c, d) {
    if (t < d/2) return easingFuncs.easeInBounce (t*2, 0, c, d) * .5 + b;
    return easingFuncs.easeOutBounce (t*2-d, 0, c, d) * .5 + c*.5 + b;
  }
}

// ease in
$easeInSine: cubic-bezier(0.12, 0, 0.39, 0);
$easeInCubic: cubic-bezier(0.32, 0, 0.67, 0);
$easeInQuint: cubic-bezier(0.64, 0, 0.78, 0);
$easeInCirc: cubic-bezier(0.55, 0, 1, 0.45);
$easeInQuad: cubic-bezier(0.11, 0, 0.5, 0);
$easeInQuart: cubic-bezier(0.5, 0, 0.75, 0);
$easeInExpo: cubic-bezier(0.7, 0, 0.84, 0);
$easeInBack: cubic-bezier(0.36, 0, 0.66, -0.56);
// ease out
$easeOutSine: cubic-bezier(0.61, 1, 0.88, 1);
$easeOutCubic: cubic-bezier(0.33, 1, 0.68, 1);
$easeOutQuint: cubic-bezier(0.22, 1, 0.36, 1);
$easeOutCirc: cubic-bezier(0, 0.55, 0.45, 1);
$easeOutQuad: cubic-bezier(0.5, 1, 0.89, 1);
$easeOutQuart: cubic-bezier(0.25, 1, 0.5, 1);
$easeOutExpo: cubic-bezier(0.16, 1, 0.3, 1);
$easeOutBack: cubic-bezier(0.34, 1.56, 0.64, 1);
// ease in out
$easeInOutSine: cubic-bezier(0.37, 0, 0.63, 1);
$easeInOutCubic: cubic-bezier(0.65, 0, 0.35, 1);
$easeInOutQuint: cubic-bezier(0.83, 0, 0.17, 1);
$easeInOutCirc: cubic-bezier(0.85, 0, 0.15, 1);
$easeInOutQuad: cubic-bezier(0.45, 0, 0.55, 1);
$easeInOutQuart: cubic-bezier(0.76, 0, 0.24, 1);
$easeInOutExpo: cubic-bezier(0.87, 0, 0.13, 1);
$easeInOutBack: cubic-bezier(0.68, -0.6, 0.32, 1.6);

// use easing
$easein: $easeInExpo;
$easeout: $easeOutExpo;
$easeinout: $easeInOutExpo;