Anime.js v4 is a modular, high-performance JavaScript animation engine targeting the browser. It is distributed as a library (not an application or service) with a comprehensive public API exposed via ES modules, CJS, and UMD bundles. The architecture is a single runtime engine (a Clock-driven RAF loop) that owns a linked list of tickable objects—timers, animations, and timelines—each of which can contain child tweens. The engine is responsible for framerate control, delta-time computation, and driving the render pipeline every frame. The core data flow is: user calls (e.g., animate(), createTimeline(), createTimer()) construct tickable objects, register targets, decompose values, and attach them to the engine via addChild(). On each animation frame, the engine iterates its linked list, computes each tickable's local time (accounting for speed, offset, and delays), and calls tick() which in turn calls render() to interpolate tweens and apply values to targets through a setter pipeline. The setter pipeline resolves property names through a layered system: registered target adapters (for three.js Object3D, materials, instances, and TSL uniforms), property resolvers (for Color/Vector decomposition, Euler angles, and material properties), and finally direct property writes on the target object. Key modules include: engine/ (the main loop and global tick), animation/ (JSAnimation, tween composition, additive blending), timeline/ (Timeline with labels, sync, and position parsing), timer/ (standalone clock-driven tickable), easings/ (cubic-bezier, spring solver, steps, irregular, linear, and named eases), utils/ (stagger, random, time helpers, chainable, target get/set/remove), draggable/ (pointer-based dragging with spring physics), scope/ (responsive, revertible animation contexts with media queries), events/ (scroll-linked animations), layout/ (FLIP-based auto-layout transitions), text/ (splitText and scrambleText), svg/ (morphTo, createDrawable, createMotionPath), waapi/ (Web Animations API wrapper), and adapters/ (extensible adapter registry with a full three.js integration). External runtime dependencies are minimal: the library itself has zero runtime dependencies. The three.js adapter is an optional peer dependency. Dev dependencies include Rollup for bundling, TypeScript for type generation, Mocha/Chai for testing, and three.js for the adapter tests. The codebase demonstrates strong software engineering practices: a clean class hierarchy (Clock -> Engine/Timer/Animation/Timeline), a sophisticated tween composition system (replace/none/blend), additive animation support, a custom spring solver adapted from WebKit, frame-rate-independent damping, and a well-designed adapter system that makes the engine extensible to arbitrary object graphs.
react-bits is a comprehensive open-source library of animated, interactive React components, accompanied by a full documentation and demo site. The repository contains hundreds of self-contained components spanning text animations, background effects, UI micro-interactions, and complete widgets, each offered in four variants (JavaScript/TypeScript × CSS/Tailwind) and distributed via a custom jsrepo registry that allows direct code copying or CLI installation (shadcn/jsrepo). The architecture is a hybrid of a component distribution platform and a marketing/demo site: `src/content`, `src/tailwind`, `src/ts-default`, and `src/ts-tailwind` contain the actual component sources, while `src/demo` and `src/components` host a Chakra UI–based playground with live prop editing, code previews, prop tables, and dependency listings. The project heavily leverages modern animation and WebGL libraries — GSAP, Framer Motion (motion/react), OGL, Three.js, and Matter.js — with many components implementing custom shaders, physics simulations, and gesture handling. While the codebase exhibits strong craftsmanship in individual components (clean hooks, accessibility attributes, cleanup of WebGL contexts, reduced-motion support), it suffers from notable duplication across the four variant directories, which risks behavioral drift and increases maintenance burden. Despite this, the library is actively maintained, well-documented, and genuinely reusable, making it a valuable resource for front-end developers seeking production-ready animated UI patterns.
Animatelo is a JavaScript library that provides a collection of pre-built animations using the Web Animations API. It ports the popular animate.css library to the JavaScript-based animation model, allowing developers to apply animations like bounce, fade, slide, and more to DOM elements via a simple API (e.g., animatelo.bounce('#element')). The library consists of a core animation engine (src/animatelo.js) that handles element selection, option validation, and animation creation, with individual animation files defining keyframe sequences for specific effects. The architecture is modular, with each animation encapsulated in its own file that extends the main animatelo object, and a build process (via Gulp) concatenates and minifies the source for distribution. The library relies on the Web Animations API (with polyfill support for older browsers) and has no runtime dependencies, making it lightweight and easy to integrate into web projects.
This repository is a Claude Code plugin and design system library for generating zero-dependency HTML presentations. It provides a structured workflow (SKILL.md) for an AI agent to create single-file slide decks with inline CSS/JS, featuring 34+ curated design templates (bold-template-pack) with detailed color palettes, typography scales, component definitions, and CJK internationalization guidance. The core runtime component is a reusable `<deck-stage>` web component that handles slide navigation, keyboard controls, auto-scaling, print support, and speaker notes. Supporting scripts enable Vercel deployment, PDF export via Playwright, and PowerPoint-to-JSON extraction. The repository is primarily a design specification library consumed by an AI coding agent, not a standalone application. It exhibits a hybrid nature: the templates are extensive design documentation (not executable code), while the plugin infrastructure and web component are functional code. The design philosophy emphasizes anti-generic aesthetics, fixed 16:9 stage scaling, and progressive disclosure of supporting files. Notable duplication exists between root and plugin paths, and all templates are marked alpha.
skrollr is a standalone, zero-dependency JavaScript library for creating parallax scrolling effects and scroll-driven animations. It operates by reading HTML5 `data-` attributes on elements to define keyframes (sets of CSS property values) at specific scroll positions, then interpolates between them as the user scrolls. The library supports both absolute mode (keyframes tied to document scroll offset) and relative mode (keyframes triggered by element position relative to the viewport), along with per-property easing functions, constants, and percentage-based offsets. It handles vendor prefixes automatically and includes a custom mobile mode that replaces native scrolling with CSS transforms for touch devices. The core rendering loop uses requestAnimationFrame, and the library exposes a clean public API for programmatic control (scroll, animate, refresh, destroy). Despite being feature-rich and well-documented, the codebase has not been actively maintained since 2014, relies on outdated build tools (Grunt, Node 0.10), and contains legacy patterns (e.g., user-agent sniffing for mobile detection). Its architecture is a single-file singleton with internal state, making it straightforward to use but harder to integrate with modern module systems without the provided AMD/CommonJS shims.