混合两种缓动效果

//just feed in the starting ease and the ending ease (and optionally an ease to do the blending), and it'll return a new Ease that's...blended!
function blendEases(startEase, endEase, blender) {
  var parse = function (ease) {
      return typeof ease === "function" ? ease : gsap.parseEase("power4.inOut");
    },
    s = gsap.parseEase(startEase),
    e = gsap.parseEase(endEase),
    blender = parse(blender);
  return function (v) {
    var b = blender(v);
    return s(v) * (1 - b) + e(v) * b;
  };
}
//example usage:
gsap.to("#target", {
  duration: 2,
  x: 100,
  ease: blendEases("back.in(1.2)", "bounce"),
});