Vue.js 3 core framework (v3.5.43) — a TypeScript library for building user interfaces, organized as a pnpm monorepo. The codebase is split into focused packages: compiler-* (template → render function compilation), runtime-* (component model, virtual DOM patching, DOM platform bindings), reactivity (dependency-tracked state), server-renderer (SSR), and shared (internal utilities). The packages/vue directory aggregates the public API surface, while vue-compat provides Vue 2 compatibility mode.
Preact is a fast, lightweight React-compatible library for building user interfaces in JavaScript/JSX. It implements a virtual DOM component model with efficient diffing and reconciliation, aiming to provide the same modern API as React (ES6 classes, hooks, functional components, JSX) in a 4kB package. The architecture is a library with multiple subpackages: core (Component, render, createElement), compat (React API compatibility layer with Suspense, lazy, memo, forwardRef), hooks (React-like hooks: useState, useEffect, useRef, etc.), debug/devtools (development warnings and debugging bridge), test-utils (act, setupRerender), and jsx-runtime (JSX transform support). Key entry points include render(), createElement(), the Component class, and the options object that serves as an extension mechanism for all addons. Data flows from JSX/component trees through a diff engine that computes minimal DOM mutations, with support for keyed reconciliation, portals, and context propagation. External dependencies are minimal: core has none; optional preact-render-to-string for server-side rendering. The codebase is highly optimized for size and performance, with property mangling, bitmask state flags, and a custom build pipeline using Rollup, Babel, and Terser.
Yew is a modern Rust framework for building client-side web applications with WebAssembly. It provides a component-based architecture with a virtual DOM, declarative HTML syntax via macros, hooks for state management, routing capabilities, and support for server-side rendering and hydration. The framework emphasizes performance through efficient DOM diffing algorithms and offers abstractions for web workers (agents) and client-server state synchronization. Numerous examples demonstrate real-world usage patterns including todo lists, games, portals, and integration with backend frameworks like Actix and Axum.
ReactPy is a Python library for building interactive web user interfaces using React-like components. Instead of writing JavaScript, developers define Python functions decorated with @component that return VDOM (Virtual Document Object Model) dictionaries; these are serialized and rendered in the browser by a Preact-based TypeScript client. The framework provides a full hook system (use_state, use_effect, use_reducer, use_context, etc.), an event-handling layer supporting debounce, throttle, and live browser-object proxies, and first-class ASGI integration via middleware or standalone ASGI apps. It also supports PyScript/Pyodide for running components entirely in the browser and importing actual ReactJS/NPM components from Python. The architecture is a hybrid library/framework: a Python core package (src/reactpy) handles component lifecycle, layout rendering, event dispatch, and state management, while a separate JavaScript client package (src/js/packages/@reactpy/client) handles DOM rendering and WebSocket communication. A notable design feature is the live event proxy, which avoids serializing entire browser event objects to the server; instead, the client holds event objects and lets Python code lazily read properties or invoke methods over a batched, security-blocklisted protocol. The project is well-tested with unit tests, Playwright-based integration tests, and CI across multiple Python versions and operating systems. It is not a data pipeline or research codebase; data-related content appears only as demo examples. The repository also contains substantial documentation, example galleries, build tooling for both Python and JavaScript, and testing fixtures that are useful for any project needing browser-backed backend testing. Some legacy APIs (e.g., reactpy.web) coexist with newer reactjs-based APIs, and the documentation has areas marked under construction, but the core code is actively maintained and demonstrates strong engineering practices.
hastscript is a utility for creating Hast (HTML Abstract Syntax Tree) trees using a hyperscript-like API. It provides two main functions, `h` for HTML and `s` for SVG, which accept CSS-like selectors, properties, and children to construct virtual DOM nodes. The library is designed to be used in build tools and frameworks that work with the Hast syntax tree, such as those in the Unified collective. The core of the library is the `createH` function in `lib/create-h.js`, which is a parameterized hyperscript function that can be adapted for different domains (like HTML or SVG) by providing a schema and default tag name. Additionally, the library supports JSX via automatic and classic runtimes, implemented in `lib/create-automatic-runtime.js` and wired up in `lib/index.js`. The project is well-maintained, with recent commits and active CI workflows, and shows low technical drift with up-to-date dependencies.