gsap.registerEase()

Use gsap.registerEase() to register your own easing function with GSAP, giving it a name that can be referenced in any animations. These eases generally return values between 0 and 1 but can go outside of that range (like GSAP's elastic ease).

For example:

gsap.registerEase("myEaseName", function (progress) {
  return progress; //linear
});

//now we can apply the ease in any tween like:
gsap.to(".class", { x: 100, ease: "myEaseName" });