VoltX.js

A lightweight reactive framework for declarative UIs. Build interactive applications using only HTML attributes powered by signals.

Features

• Declarative, HTML-first reactivity via data-volt-* attributes
• Fine-grained signals and effects that update the DOM without a virtual DOM
• Zero runtime dependencies and a sub-15 KB gzipped core
• Built-in transport for SSE/WebSocket streams and JSON Patch updates
• Hydration-friendly rendering with SSR helpers
• Optional CSS design system and debug overlay for inspecting signal graphs

Installation

npm

npm install voltx.js

JSR

npx jsr add @voltx/core

Deno

import { charge, signal } from "jsr:@voltx/core";

Quick Start

<div data-volt data-volt-state='{"count": 0}'>
  <p data-volt-text="count"></p>
  <button data-volt-on-click="count.set(count.get() + 1)">Increment</button>
</div>

<script type="module">
  import { charge } from 'voltx.js';
  charge();
</script>

Plugins

• data-volt-persist – automatically sync state across reloads and tabs
• data-volt-url – keep signals in sync with query params and hashes
• data-volt-scroll – manage scroll restoration and anchored navigation
• data-volt-shift – trigger reusable keyframe animations
• data-volt-surge – apply enter/leave transitions with view-transition support

Plugins are opt-in and can be combined declaratively or registered programmatically via charge({ plugins: [...] }).

VoltX.css

VoltX ships with an optional classless CSS framework inspired by Pico CSS and Tufte CSS. It provides beautiful, semantic styling without requiring any CSS classes. Just write semantic HTML and it looks great. It's perfect for prototyping.

Features

• Typography: Modular scale (1.25 ratio), harmonious spacing, and responsive sizing
• Tufte-style sidenotes: Margin notes using <small> that float on desktop, inline on mobile
• Components: Styled dialogs, accordions (details/summary), and pure-CSS tooltips
• Forms: Consistent, accessible input styling with validation states
• Tables: Zebra striping and responsive behavior
• Code blocks: Syntax-appropriate styling for inline and block code
• Dark mode: Automatic theme switching based on system preferences

Installation

Import the CSS in your application:

import 'voltx.js/css';

Or include via CDN:

<link rel="stylesheet" href="https://unpkg.com/voltx.js/dist/voltx.css">

Usage

No classes needed. Just write semantic HTML:

<article>
  <h2>Beautiful Typography</h2>
  <p>
    This paragraph has proper spacing.
    <small>This sidenote appears in the margin on wide screens.</small>
    All elements are styled automatically.
  </p>

  <details>
    <summary>Accordion Example</summary>
    <p>Content revealed when opened.</p>
  </details>
</article>

See the demo app's CSS section for comprehensive examples of all features.

Documentation

Full documentation available at https://stormlightlabs.github.io/volt/

Development

• pnpm install (at the repo root) to bootstrap the workspace
• pnpm --filter lib dev runs package scripts such as build, test, and typecheck
• pnpm dev spins up the playground in lib/dev for interactive testing

License

MIT