gsap（GSAP 动画开发）

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

Reference Index

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

Plugin Availability