gsap

SKILL.md

GSAP Best Practices

Professional-grade JavaScript animation library for the modern web. Provides high-performance tweening with powerful sequencing, scroll-based animations, and extensive plugin ecosystem.

Installation

# Core library
npm install gsap

# React hook
npm install @gsap/react

# Register plugins (do once at app entry)
import gsap from 'gsap'
import { ScrollTrigger } from 'gsap/ScrollTrigger'
gsap.registerPlugin(ScrollTrigger)

Quick Start

import gsap from 'gsap'

// Basic tween
gsap.to('.box', { x: 200, duration: 1 })

// From animation
gsap.from('.box', { opacity: 0, y: 50, duration: 0.5 })

// Timeline sequence
const tl = gsap.timeline()
tl.to('.box1', { x: 100 })
  .to('.box2', { x: 100 }, '-=0.5')  // overlap by 0.5s
  .to('.box3', { x: 100 }, '<')       // same start as previous

Core Concepts

Concept Description
Tween Single animation that changes properties over time
Timeline Container for sequencing tweens with precise control
Ease Controls animation velocity curve (default: power1.out)
ScrollTrigger Links animations to scroll position
Plugin Extends GSAP with specialized capabilities

Reference Index

Reference Use When
references/00-cheatsheet.md Quick reference, common operations at a glance
references/01-core.md Basic tweens, special properties, callbacks, quickTo, ticker
references/02-easing.md Easing functions, custom eases
references/03-timeline.md Sequencing, positioning, labels, nesting
references/04-stagger.md Staggered animations, grid distributions
references/05-utilities.md Helper functions (toArray, clamp, interpolate)
references/06-scrolltrigger.md Scroll-based animations, pin, scrub, snap
references/07-scrollsmoother.md Smooth scrolling, parallax effects
references/08-splittext.md Text splitting and animation
references/09-svg-plugins.md DrawSVG, MorphSVG, MotionPath
references/10-flip.md Layout animations (FLIP technique)
references/11-react.md useGSAP hook, cleanup, React patterns
references/12-observer-draggable.md Gesture detection, draggable elements
references/13-text-plugins.md TextPlugin, ScrambleTextPlugin

Common Patterns

Fade In on Load

gsap.from('.hero', {
  opacity: 0,
  y: 30,
  duration: 1,
  ease: 'power2.out'
})

Staggered List Animation

gsap.from('.list-item', {
  opacity: 0,
  y: 20,
  stagger: 0.1,
  duration: 0.5
})

Scroll-Triggered Animation

gsap.registerPlugin(ScrollTrigger)

gsap.to('.box', {
  x: 500,
  scrollTrigger: {
    trigger: '.box',
    start: 'top 80%',
    end: 'top 20%',
    scrub: true
  }
})

Timeline with Controls

const tl = gsap.timeline({ paused: true })
tl.to('.modal', { opacity: 1, scale: 1, duration: 0.3 })
  .from('.modal-content', { y: 20, opacity: 0 }, '-=0.1')

// Control playback
tl.play()
tl.reverse()
tl.progress(0.5)

Critical Mistakes to Avoid

1. Missing Plugin Registration

// ❌ Plugin won't work
import { ScrollTrigger } from 'gsap/ScrollTrigger'
gsap.to('.box', { scrollTrigger: { ... } })

// ✅ Register plugins first
gsap.registerPlugin(ScrollTrigger)
gsap.to('.box', { scrollTrigger: { ... } })

2. React Cleanup Issues

// ❌ Memory leaks, zombie animations
useEffect(() => {
  gsap.to('.box', { x: 100 })
}, [])

// ✅ Use useGSAP hook for automatic cleanup
import { useGSAP } from '@gsap/react'
useGSAP(() => {
  gsap.to('.box', { x: 100 })
}, { scope: containerRef })

3. Conflicting Tweens

// ❌ Two tweens fighting for same property
gsap.to('.box', { x: 100, duration: 2 })
gsap.to('.box', { x: 200, duration: 1 })

// ✅ Use overwrite or kill previous
gsap.to('.box', { x: 100, duration: 2, overwrite: true })
// or
gsap.killTweensOf('.box')
gsap.to('.box', { x: 200, duration: 1 })

4. ScrollTrigger Not Refreshing

// ❌ Layout changes but ScrollTrigger uses old positions
dynamicallyAddContent()

// ✅ Refresh after DOM/layout changes
dynamicallyAddContent()
ScrollTrigger.refresh()

5. Animating Non-Existent Elements

// ❌ Element not in DOM yet
gsap.to('.dynamic-element', { x: 100 })

// ✅ Wait for element or use immediateRender: false
gsap.to('.dynamic-element', {
  x: 100,
  immediateRender: false,
  scrollTrigger: { ... }
})

6. Wrong from() Behavior

// ❌ from() renders immediately, causing flash
gsap.from('.box', { opacity: 0 })

// ✅ Set initial state in CSS or use fromTo
// CSS: .box { opacity: 0; }
gsap.to('.box', { opacity: 1 })

// or use fromTo for explicit control
gsap.fromTo('.box', { opacity: 0 }, { opacity: 1 })

7. Forgetting Selector Scope

// ❌ Affects ALL .box elements on page
gsap.to('.box', { x: 100 })

// ✅ Scope to container
gsap.to('.box', { x: 100 }, { scope: containerRef })
// or use gsap.utils.selector
const q = gsap.utils.selector(container)
gsap.to(q('.box'), { x: 100 })

Quick Reference

Task Solution
Animate to values gsap.to(target, { props })
Animate from values gsap.from(target, { props })
Animate both directions gsap.fromTo(target, { from }, { to })
Set instantly gsap.set(target, { props })
Create timeline gsap.timeline({ options })
Kill all tweens gsap.killTweensOf(target)
Global defaults gsap.defaults({ ease, duration })
Register plugin gsap.registerPlugin(Plugin)
Get by ID gsap.getById('myTween')
Match media gsap.matchMedia()

Plugin Availability

Plugin License Description
ScrollTrigger Free Scroll-based animations
Observer Free Gesture/scroll detection
Draggable Free Drag interactions
Flip Free Layout animations
TextPlugin Free Text content animation
ScrollSmoother Club Smooth scrolling
SplitText Club Text splitting
DrawSVG Club SVG stroke animation
MorphSVG Club SVG morphing
MotionPath Club Path-based motion
ScrollTo Free Scroll to position
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