v0.1.2

Fix h() rest-arg type to accept array children. The 0.1.1 runtime change made h(tag, props, items.map(...)) flatten correctly, but ChildArg was left
non-recursive so the call site still failed type-checking. ChildArg is now VNode | string | number | null | undefined | ChildArg[].

v0.1.1

Patch release.

Fixed

• h() rest-arg API now flattens a single array child, matching React's and Inferno's createElement. Previously, the single-child fast path in normalizeChildren did not call Array.isArray, so a call like:

  h("ul", null, items.map((item) => h("li", { key: item.id }, item.label)))

  stored the array itself as a single VNode child instead of flattening it, producing broken output. Users had to spread the array (...items.map(...)) to work around it. The multi-child path already handled arrays correctly; this brings the length-1 path in line.

  Fixes the migration story for code coming from React or Inferno's createElement call sites. JSX users were unaffected because the JSX automatic runtime (tachys/jsx-runtime) was already array-aware.

Install

pnpm add tachys@0.1.1

Full diff: v0.1.0...v0.1.1

v0.1.0

First public release of Tachys.

Tachys is a high-performance virtual DOM library with a React-compatible API. On the Krausest js-framework-benchmark, it matches Inferno on click-to-paint time (1.007x geomean) and is ~18% faster on script time (0.823x geomean). Core runtime is ~36KB minified, ~11KB gzipped, zero dependencies.

Packages

Package	Description
tachys	Core runtime: VDOM, hooks, Suspense, ErrorBoundary, streaming SSR, hydration, concurrent scheduler
babel-plugin-tachys	Compiles JSX components to markCompiled + _template form, skipping the VDOM at runtime
swc-plugin-tachys	Same compile pipeline, parsed via @swc/core for SWC-based toolchains
compiler-core-tachys	Shared portable IR + emitter used by both compiler frontends
tachys-aeon	Aeon FRP integration: Behavior and Event as first-class UI primitives via hooks

What's in core

• Function components and hooks: useState, useReducer, useEffect, useLayoutEffect, useMemo, useCallback, useRef, useContext, useTransition, useDeferredValue, useId, useSyncExternalStore, use
• memo, forwardRef, lazy, createPortal, createRef
• Suspense + ErrorBoundary (works with lazy() and use(promise))
• Streaming SSR (renderToReadableStream) with selective hydration
• Concurrent scheduler with priority lanes
• React compatibility shim (tachys/compat) so existing React code can import from Tachys
• Lean entry points (tachys/sync, tachys/sync-core) that drop the concurrent scheduler and Suspense for apps that don't need them

Install

pnpm add tachys

JSX setup, full API, and architecture notes: https://joshburgess.github.io/tachys/

Notes

• Dual-licensed under MIT or Apache-2.0
• Requires Node.js >= 18
• 962 tests passing across 55 files