react-gsap Docs
Introduction
Components
Plugins
Instructions
EasingEase function with parametersSlowMo easeCustom easing functionLow-level accessMigration from version 1Use "playState" prop

Easing

With GSAP 3 the easing functions are more easily usable as string without importing. They can be used in the "ease" prop of the Tween.

Have a look at the docs: https://greensock.com/docs/v3/Eases

The default is power1.out. You can overide the defaults if you want: https://greensock.com/docs/v3/GSAP/gsap.defaults().

import { Controls, PlayState, Tween } from 'react-gsap';

Ease function with parameters

SlowMo ease

This is an extra ease that has to be registered first:

import { gsap } from 'gsap';
import { SlowMo } from 'gsap/EasePack';
gsap.registerPlugin(SlowMo);

Custom easing function

You can also pass a function to the ease prop. In this way you can have your custom easing functions.

In the example it's an easeInOutQuart. Take a look at this resource for inspiration: https://easings.net/