Gsap TimelineSAFE

Official AI skills for GSAP. These skills teach AI coding agents how to correctly use GSAP (GreenSock Animation Platform), including best practices, common animation patterns, and plugin usage.

The instruction file, verbatim from the audited commit — this is the text the model reads, and the surface the audit's instruction layer examines. Quoted here so you can judge it without cloning anything.

---
name: gsap-timeline
description: Official GSAP skill for timelines — gsap.timeline(), position parameter, nesting, playback. Use when sequencing animations, choreographing keyframes, or when the user asks about animation sequencing, timelines, or animation order (in GSAP or when recommending a library that supports timelines).
license: MIT
---

# GSAP Timeline

## When to Use This Skill

Apply when building multi-step animations, coordinating several tweens in sequence or parallel, or when the user asks about timelines, sequencing, or keyframe-style animation in GSAP.

**Related skills:** For single tweens and eases use **gsap-core**; for scroll-driven timelines use **gsap-scrolltrigger**; for React use **gsap-react**.

## Creating a Timeline

```javascript
const tl = gsap.timeline();
tl.to(".a", { x: 100, duration: 1 })
  .to(".b", { y: 50, duration: 0.5 })
  .to(".c", { opacity: 0, duration: 0.3 });
```

By default, tweens are **appended** one after another. Use the **position parameter** to place tweens at specific times or relative to other tweens.

## Position Parameter

Third argument (or position property in vars) controls placement:

- **Absolute**: `1` — start at 1 second.
- **Relative (default)**: `"+=0.5"` — 0.5s after end; `"-=0.2"` — 0.2s before end.
- **Label**: `"labelName"` — at that label; `"labelName+=0.3"` — 0.3s after label.
- **Placement**: `"<"` — start when recently-added animation starts; `">"` — start when recently-added animation ends (default); `"<0.2"` — 0.2s after recently-added animation start.

Examples:

```javascript
tl.to(".a", { x: 100 }, 0);           // at 0
tl.to(".b", { y: 50 }, "+=0.5");      // 0.5s after last end
tl.to(".c", { opacity: 0 }, "<");     // same start as previous
tl.to(".d", { scale: 2 }, "<0.2");    // 0.2s after previous start
```

## Timeline Defaults

Pass defaults into the timeline so all child tweens inherit:

```javascript
const tl = gsap.timeline({ defaults: { duration: 0.5, ease: "power2.out" } });
tl.to(".a", { x: 100 }).to(".b", { y: 50 }); // both use 0.5s and power2.out
```

## Timeline Options (constructor)

- **paused: true** — create paused; call `.play()` to start.
- **repeat**, **yoyo** — same as tweens; apply to whole timeline.
- **onComplete**, **onStart**, **onUpdate** — timeline-level callbacks.
- **defaults** — vars merged into every child tween.

## Labels

Add and use labels for readable, maintainable sequencing:

```javascript
tl.addLabel("intro", 0);
tl.to(".a", { x: 100 }, "intro");
tl.addLabel("outro", "+=0.5");
tl.to(".b", { opacity: 0 }, "outro");
tl.play("outro");  // start from "outro"
tl.tweenFromTo("intro", "outro"); // pauses the timeline and returns a new Tween that animates the timeline's playhead from intro to outro with no ease.
```

## Nesting Timelines

Timelines can contain other timelines.

```javascript
const master = gsap.timeline();
const child = gsap.timeline();
child.to(".a", { x: 100 }).to(".b", { y: 50 });
master.add(child, 0);
master.to(".c", { opacity: 0 }, "+=0.2");
```

## Controlling Playback

- **tl.play()** / **tl.pause()**
- **tl.reverse()** / **tl.progress(1)** then **tl.reverse()**
- **tl.restart()** — from start.
- **tl.time(2)** — seek to 2 seconds.
- **tl.progress(0.5)** — seek to 50%.
- **tl.kill()** — kill timeline and (by default) its children.

## Official GSAP Best practices

- ✅ Prefer timelines for sequencing
- ✅ Use the **position parameter** (third argument) to place tweens at specific times or relative to labels.
- ✅ Add **labels** with `addLabel()` for readable, maintainable sequencing.
- ✅ Pass **defaults** into the timeline constructor so child tweens inherit duration, ease, etc.
- ✅ Put ScrollTrigger on the timeline (or top-level tween), not on tweens inside a timeline.

## Do Not

- ❌ Chain animations with **delay** when a **timeline** can sequence them; prefer `gsap.timeline()` and the position parameter for multi-step animation.
- ❌ Forget to pass **defaults** (e.g. `defaults: { duration: 0.5, ease: "power2.out" }`) when many child tweens share the same duration or ease.
- ❌ Forget that **duration** on the timeline constructor is not the same as tween duration; timeline “duration” is determined by its children.
- ❌ Nest animations that contain a ScrollTrigger; ScrollTriggers should only be on top-level Tweens/Timelines.

SAFEgrade B · trust 89/100 Nothing in the source contradicts what it says it does. Grade A is reserved for packages that have also passed the behavioural sandbox.

What the source does

Filesystem

none-observed

Network

none-observed

Shell

none-observed

Dependencies

pinned

Secrets in source

none-found

Findings (2)

CLAUDE.md

GEMINI.md

Gates applied: no_behavioural_pass.

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