/gsap-performance

name: gsap-performance
description: |
  Official GSAP skill for performance — prefer transforms, avoid layout thrashing, will-change, batching. Use when optimizing GSAP animations, reducing jank, or when the user asks about animation performance, FPS, or smooth 60fps.
zh_name: "GSAP · 动效性能"
zh_description: "排查 GSAP 动画卡顿，优化布局、合成层、资源清理与运行成本。"
triggers:
  - "动效"
  - "动画"
  - "motion"
  - "动效性能"
  - "动画卡顿"
  - "gsap performance"
  - "animation jank"
  - "60fps animation"
  - "will-change"
  - "layout thrashing"
license: MIT
od:
  mode: utility
  category: animation-motion
  source-commit: aed9cfd3277740755f6bfc1155c7aa645403b760
  upstream: "https://github.com/greensock/gsap-skills"

GSAP Performance

> Curated from GreenSock's official GSAP skills: https://github.com/greensock/gsap-skills

When to Use This Skill

Apply when optimizing GSAP animations for smooth 60fps, reducing layout/paint cost, or when the user asks about performance, jank, or best practices for fast animations.

**Related skills:** Build animations with **gsap-core** (transforms, autoAlpha) and **gsap-timeline**; for ScrollTrigger performance see **gsap-scrolltrigger**.

Prefer Transform and Opacity

Animating **transform** (`x`, `y`, `scaleX`, `scaleY`, `rotation`, `rotationX`, `rotationY`, `skewX`, `skewY`) and **opacity** keeps work on the compositor and avoids layout and most paint. Avoid animating layout-heavy properties when a transform can achieve the same effect.

• ✅ Prefer: **x**, **y**, **scale**, **rotation**, **opacity**.
• ❌ Avoid when possible: **width**, **height**, **top**, **left**, **margin**, **padding** (they trigger layout and can cause jank).

GSAP’s **x** and **y** use transforms (translate) by default; use them instead of **left**/**top** for movement.

will-change

Use **will-change** in CSS on elements that will animate. It hints the browser to promote the layer.

will-change: transform;

Batch Reads and Writes

GSAP batches updates internally. When mixing GSAP with direct DOM reads/writes or layout-dependent code, avoid interleaving reads and writes in a way that causes repeated layout thrashing. Prefer doing all reads first, then all writes (or let GSAP handle the writes in one go).

Many Elements (Stagger, Lists)

• Use **stagger** instead of many separate tweens with manual delays when the animation is the same; it’s more efficient.
• For long lists, consider **virtualization** or animating only visible items; avoid creating hundreds of simultaneous tweens if it causes jank.
• Reuse timelines where possible; avoid creating new timelines every frame.

Frequently updated properties (e.g. mouse followers)

Prefer **gsap.quickTo()** for properties that are updated often (e.g. mouse-follower x/y). It reuses a single tween instead of creating new tweens on each update.

let xTo = gsap.quickTo("#id", "x", { duration: 0.4, ease: "power3" }),
    yTo = gsap.quickTo("#id", "y", { duration: 0.4, ease: "power3" });

document.querySelector("#container").addEventListener("mousemove", (e) => {
  xTo(e.pageX);
  yTo(e.pageY);
});

ScrollTrigger and Performance

• **pin: true** promotes the pinned element; pin only what’s needed.
• **scrub** with a small value (e.g. `scrub: 1`) can reduce work during scroll; test on low-end devices.
• Call **ScrollTrigger.refresh()** only when layout actually changes (e.g. after content load), not on every resize; debounce when possible.

Reduce Simultaneous Work

• Pause or kill off-screen or inactive animations when they’re not visible (e.g. when the user navigates away).
• Avoid animating huge numbers of properties on many elements at once; simplify or sequence if needed.

Best practices

• ✅ Animate **transform** and **opacity**; use **will-change** in CSS only on elements that animate.
• ✅ Use **stagger** instead of many separate tweens with manual delays when the animation is the same.
• ✅ Use **gsap.quickTo()** for frequently updated properties (e.g. mouse followers).
• ✅ Clean up or kill off-screen animations; call **ScrollTrigger.refresh()** when layout changes, debounced when possible.

Do Not

• ❌ Animate **width**/ **height**/ **top**/ **left** for movement when **x**/ **y**/ **scale** can achieve the same look.
• ❌ Set **will-change** or **force3D** on every element “just in case”; use for elements that are actually animating.
• ❌ Create hundreds of overlapping tweens or ScrollTriggers without testing on low-end devices.
• ❌ Ignore cleanup; stray tweens and ScrollTriggers keep running and can hurt performance and correctness.