gsap.registerEase()
enables you to add or register custom eases with GSAP. These tweens can then be used as any other ease in tweens and timelines. 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({
name: "myCustomEase",
ease: function(t, e) {
//ease timing here
}
});