Animejs

anime.js v4 Animation

You are an expert in anime.js v4 (latest: v4.3.5), the lightweight JavaScript animation library. Generate production-ready animation code using the v4 API exclusively. Never use v3 syntax.

CRITICAL: v4 API Only

anime.js v4 introduced breaking changes from v3. ALWAYS use v4 syntax:

Installation & Setup

CDN:

<script src="https://cdn.jsdelivr.net/npm/animejs@4/lib/anime.iife.min.js"></script>

npm:

npm install animejs

ES Module imports (recommended):

import { animate, stagger, createTimeline } from 'animejs';
// Additional features — import only what you need:
import { createAnimatable } from 'animejs';
import { createDraggable } from 'animejs';
import { createLayout } from 'animejs';
import { onScroll } from 'animejs';
import { waapi } from 'animejs';
import { svg } from 'animejs';
import { splitText } from 'animejs';
import { engine, utils } from 'animejs';

Subpath imports (tree-shaking):

import { animate } from 'animejs/animation';
import { createTimeline } from 'animejs/timeline';
import { createDraggable } from 'animejs/draggable';
import { onScroll } from 'animejs/events';
import { splitText } from 'animejs/text';

Core: animate(targets, parameters)

Targets

// CSS selector
animate('.box', { ... });

// DOM element
animate(document.querySelector('#hero'), { ... });

// Multiple elements (NodeList, Array)
animate(document.querySelectorAll('.card'), { ... });

// JavaScript object (animate numeric properties)
const obj = { progress: 0 };
animate(obj, { progress: 100, onUpdate: () => console.log(obj.progress) });

Parameters

Callbacks

animate('.el', {
  translateX: 250,
  onBegin: (anim) => {},      // When animation starts (after delay)
  onUpdate: (anim) => {},     // Every frame
  onComplete: (anim) => {},   // When animation finishes
  onLoop: (anim) => {},       // After each loop iteration
  onPause: (anim) => {},      // When paused
}).then((anim) => {});         // Promise-based completion

Playback Controls

const anim = animate('.el', { translateX: 250, autoplay: false });

anim.play();        // Play forward
anim.pause();       // Pause
anim.resume();      // Resume from current position and direction
anim.reverse();     // Reverse direction
anim.restart();     // Restart from beginning
anim.seek(500);     // Jump to 500ms
anim.reset();       // Reset to initial values
anim.complete();    // Jump to end
anim.cancel();      // Cancel and clean up
anim.revert();      // Revert targets to original values

Animatable Properties

animate('.el', {
  // CSS transforms
  translateX: 250,
  translateY: 100,
  rotate: '1turn',
  scale: 1.5,
  skewX: '15deg',

  // CSS properties
  opacity: [0, 1],
  backgroundColor: '#FF0000',
  borderRadius: '50%',
  width: '200px',

  // CSS variables
  '--custom-prop': 100,

  // Relative values
  translateX: '+=100',
  rotate: '-=45deg',

  // From-to syntax
  opacity: { from: 0, to: 1 },
  translateY: [50, 0],          // [from, to]

  // Per-property parameters
  translateX: { to: 250, duration: 800, ease: 'outExpo' },
  opacity: { to: 1, duration: 400, delay: 200 },

  // Function-based values (per target)
  translateX: (target, index, total) => index * 50,
  delay: (target, index) => index * 100,
});

Keyframes

Property-level (array of values):

animate('.el', {
  translateX: [0, 100, 50, 200],
  duration: 2000,
});

Property-level (array of objects):

animate('.el', {
  translateX: [
    { to: 100, duration: 500, ease: 'outQuad' },
    { to: 50, duration: 300 },
    { to: 200, duration: 700, ease: 'inOutCubic' },
  ],
});

Percentage-based:

animate('.el', {
  keyframes: {
    '0%':   { translateX: 0, opacity: 0 },
    '40%':  { translateX: 100, opacity: 1 },
    '100%': { translateX: 250, opacity: 0.5 },
  },
  duration: 2000,
});

Stagger

Distribute values or delays across multiple targets.

import { animate, stagger } from 'animejs';

// Basic delay stagger: each element starts 100ms after the previous
animate('.card', {
  opacity: [0, 1],
  translateY: [30, 0],
  delay: stagger(100),
  duration: 500,
  ease: 'outCubic',
});

// From center outward
animate('.item', { scale: [0, 1], delay: stagger(80, { from: 'center' }) });

// From edges inward
animate('.item', { scale: [0, 1], delay: stagger(80, { from: 'edges' }) });

// From specific index
animate('.item', { scale: [0, 1], delay: stagger(80, { from: 3 }) });

// Range distribution: values spread evenly between 0 and 200
animate('.item', { translateX: stagger([0, 200]) });

// Grid stagger (rows x cols)
animate('.grid-item', {
  scale: [0, 1],
  delay: stagger(50, { grid: [4, 6], from: 'center', axis: 'y' }),
});

// Eased stagger distribution
animate('.item', { opacity: [0, 1], delay: stagger(300, { ease: 'inOutQuad' }) });

Timelines

Sequence and synchronize multiple animations.

import { createTimeline, stagger } from 'animejs';

const tl = createTimeline({
  defaults: { duration: 600, ease: 'outQuad' },
});

// Animations chain sequentially by default
tl.add('.header', { opacity: [0, 1], translateY: [-30, 0] })
  .add('.subtitle', { opacity: [0, 1], translateY: [20, 0] }, '-=300')  // Overlap by 300ms
  .add('.cta-btn', { opacity: [0, 1], scale: [0.8, 1] }, '+=100')      // 100ms gap
  .add('.cards', {
    opacity: [0, 1],
    translateY: [40, 0],
    delay: stagger(80),
  }, '-=200');

// Absolute positioning (ms from timeline start)
tl.add('.bg', { opacity: [0, 0.5] }, 0);  // Starts at 0ms

// Timeline controls
tl.play();
tl.pause();
tl.seek(1000);
tl.reverse();
tl.restart();

Text Splitting

Split text into lines, words, or characters for per-element animation.

import { splitText, animate, stagger } from 'animejs';

// Split heading into characters
const splitter = splitText('.hero-title', {
  chars: true,          // Split into characters
  // words: true,       // Split into words
  // lines: true,       // Split into lines
  accessible: true,     // Maintain screen reader accessibility
});

// Animate each character
animate(splitter.chars, {
  opacity: [0, 1],
  translateY: [20, 0],
  delay: stagger(30),
  duration: 400,
  ease: 'outCubic',
});

// Revert DOM to original text when done
// splitter.revert();

Scroll Observer

Trigger and synchronize animations with scroll position.

import { animate, onScroll } from 'animejs';

// Trigger animation when element enters viewport
onScroll('.section', {
  onEnter: () => {
    animate('.section .content', {
      opacity: [0, 1],
      translateY: [40, 0],
      duration: 800,
      ease: 'outQuad',
    });
  },
});

// Directional callbacks
onScroll('.element', {
  onEnterForward: () => {},    // Scrolling down into view
  onEnterBackward: () => {},   // Scrolling up into view
  onLeaveForward: () => {},    // Scrolling down out of view
  onLeaveBackward: () => {},   // Scrolling up out of view
});

// Sync animation progress to scroll position
const anim = animate('.parallax-bg', {
  translateY: [-100, 100],
  autoplay: false,
});

onScroll('.parallax-section', {
  sync: 'playback',    // Links scroll position to animation progress
  link: anim,
});

// Thresholds
onScroll('.el', {
  enter: 'top bottom',     // When top of el crosses bottom of viewport
  leave: 'bottom top',     // When bottom of el crosses top of viewport
});

WAAPI (Web Animation API)

Lightweight 3KB alternative using browser-native Web Animation API. Hardware-accelerated. Use for simple animations where performance is critical.

import { waapi } from 'animejs';

const anim = waapi.animate('.el', {
  translateX: 250,
  opacity: [0, 1],
  duration: 600,
  ease: 'outQuad',
});

When to use WAAPI vs full animate():

• WAAPI: Simple CSS transforms/opacity, high-performance needs, many simultaneous elements
• Full animate(): JS object animation, complex keyframes, onUpdate callback, modifier functions, SVG features

Animatable

Reactive value animation — ideal for cursor tracking, interactive UIs, and frequently changing values.

import { createAnimatable } from 'animejs';

const follower = createAnimatable('.cursor-follower', {
  x: { duration: 300, ease: 'outQuad' },
  y: { duration: 300, ease: 'outQuad' },
});

document.addEventListener('mousemove', (e) => {
  follower.x(e.clientX);  // Setter: animates to value
  follower.y(e.clientY);
});

// Getter
const currentX = follower.x();

Layout Animations

Animate layout changes that are normally impossible (CSS display, grid, flex, DOM order).

import { createLayout } from 'animejs';

const layout = createLayout('.container', {
  duration: 500,
  ease: 'outQuad',
  // Enter/exit states for added/removed elements
  enterFrom: { opacity: 0, scale: 0.8 },
  leaveTo: { opacity: 0, scale: 0.8 },
});

// Animate any layout change
layout.update(() => {
  // Toggle class, change display, reorder DOM, etc.
  container.classList.toggle('grid-view');
});

// Or manual record → animate pattern
layout.record();
// ... make DOM changes ...
layout.animate();

Draggable

Add drag interaction with physics.

import { createDraggable } from 'animejs';

const draggable = createDraggable('.card', {
  x: { snap: 100 },                // Snap to 100px grid on x-axis
  y: { snap: 100 },
  friction: 0.5,                    // Drag friction
  mass: 1,                          // Physics mass
  stiffness: 100,                   // Spring stiffness
  damping: 10,                      // Spring damping
  onGrab: (self) => {},
  onDrag: (self) => {},
  onRelease: (self) => {},
  onSnap: (self) => {},
  onSettle: (self) => {},
});

// Constrain to container
const draggable = createDraggable('.el', {
  container: '.bounds',
  x: true,
  y: true,
});

SVG Features

import { animate, svg } from 'animejs';

// Line drawing (animate stroke)
const drawable = svg.createDrawable('.svg-path');
animate(drawable, { draw: [0, 1], duration: 1500, ease: 'inOutQuad' });

// Shape morphing
animate('.shape path', {
  d: svg.morphTo('.target-shape path'),
  duration: 1000,
  ease: 'inOutQuad',
});

// Motion path (move element along SVG path)
const motionPath = svg.createMotionPath('.motion-path');
animate('.moving-element', {
  ...motionPath,         // Spread the path data
  duration: 3000,
  ease: 'linear',
  loop: true,
});

Easings

Custom easings:

ease: 'cubicBezier(0.25, 0.1, 0.25, 1.0)'   // CSS cubic-bezier
ease: 'spring(1, 100, 10, 0)'                 // spring(mass, stiffness, damping, velocity)
ease: 'steps(5)'                               // Stepped animation
ease: 'linear'                                 // Constant speed

When to use which:

• Entrances: outQuad, outCubic, outExpo (fast start, slow end)
• Exits: inQuad, inCubic (slow start, fast end)
• State changes: inOutQuad, inOutCubic (smooth both ends)
• Bouncy/playful: outBack, outElastic, spring()
• Continuous/looping: linear

For the complete easing catalog with motion descriptions and presets, see references/easing-reference.md.

Engine Configuration

import { engine } from 'animejs';

engine.timeUnit = 'ms';          // 'ms' or 's'
engine.speed = 1;                // Global speed multiplier
engine.fps = 60;                 // Max frames per second
engine.precision = 4;            // Decimal precision
engine.pauseOnDocumentHidden = true;  // Pause when tab hidden

Utilities

import { utils } from 'animejs';

utils.get('.el', 'translateX');          // Get current value
utils.set('.el', { opacity: 0.5 });     // Set without animating
utils.random(0, 100);                   // Random number
utils.clamp(value, 0, 100);             // Clamp to range
utils.snap(value, 10);                  // Snap to nearest 10
utils.mapRange(value, 0, 1, 0, 100);    // Remap range
utils.lerp(start, end, 0.5);            // Linear interpolation

Selector shorthand:

import { $ } from 'animejs';
const elements = $('.card');  // Like querySelectorAll

Common Patterns

Fade in on load

animate('.element', {
  opacity: [0, 1],
  translateY: [20, 0],
  duration: 600,
  ease: 'outQuad',
});

Staggered list entrance

animate('.list-item', {
  opacity: [0, 1],
  translateY: [30, 0],
  delay: stagger(80),
  duration: 500,
  ease: 'outCubic',
});

Hover scale effect

document.querySelectorAll('.btn').forEach(btn => {
  btn.addEventListener('mouseenter', () =>
    animate(btn, { scale: 1.05, duration: 200, ease: 'outQuad' })
  );
  btn.addEventListener('mouseleave', () =>
    animate(btn, { scale: 1, duration: 200, ease: 'outQuad' })
  );
});

Loading spinner

animate('.spinner', {
  rotate: '1turn',
  duration: 800,
  loop: true,
  ease: 'linear',
});

Animated counter

const counter = { value: 0 };
animate(counter, {
  value: 2500,
  duration: 2000,
  ease: 'outExpo',
  onUpdate: () => {
    document.querySelector('.count').textContent = Math.round(counter.value);
  },
});

Scroll-triggered reveal

onScroll('.reveal-section', {
  onEnter: () => {
    animate('.reveal-section .item', {
      opacity: [0, 1],
      translateY: [40, 0],
      delay: stagger(100),
      duration: 600,
      ease: 'outCubic',
    });
  },
});

Text reveal

const splitter = splitText('.headline', { chars: true, accessible: true });
animate(splitter.chars, {
  opacity: [0, 1],
  translateY: [20, 0],
  delay: stagger(25),
  duration: 400,
  ease: 'outCubic',
});

Draggable card

createDraggable('.drag-card', {
  container: '.card-area',
  x: true,
  y: true,
  friction: 0.7,
  onRelease: (self) => {
    // Snap back or process drop
  },
});

For complete website animation patterns (hero sections, navigation effects, parallax, modals, carousels, etc.), see references/website-animation-patterns.md.

v3 to v4 Complete Migration Reference