twx-react

Runtime-first styling library for React with Tailwind-style utilities, component variants, slots, and compounds.

twx-react gives you a lightweight runtime styling layer for React. It is designed for teams that want Tailwind-style ergonomics without the overhead of a heavier styling framework.

Installation

npm install twx-react react

Core idea

Use the library for three things:

• tw for runtime utility processing and class merging
• createTwComponent for reusable, typed component primitives
• createTwSlots and createTwCompound for multi-part and grouped UI patterns

Quick start

import { tw } from 'twx-react';

export function Example() {
  return (
    <tw.button className="px-4 py-2 rounded-lg bg-blue-600 text-white hover:bg-blue-700">
      Save changes
    </tw.button>
  );
}

import { createTwComponent } from 'twx-react';

const Button = createTwComponent('button', {
  base: 'inline-flex items-center rounded-lg font-medium transition-colors',
  variants: {
    size: {
      sm: 'px-3 py-1.5 text-sm',
      md: 'px-4 py-2 text-base',
    },
    color: {
      primary: 'bg-blue-600 text-white hover:bg-blue-700',
      secondary: 'bg-gray-200 text-gray-800 hover:bg-gray-300',
    },
  },
  defaultVariants: { size: 'md', color: 'primary' },
});

For a deeper introduction, see docs/GETTING-STARTED.md.

Why it exists

• Zero build-step styling for React apps
• Deterministic class merging with twMerge
• Type-safe component variants
• Runtime CSS generation with SSR-friendly behavior
• A compact API surface focused on styling primitives

API highlights

• tw and twMerge
• createTwComponent
• createTwSlots
• createTwCompound
• useTwVariants and useTwSlots
• injectPreflight and disablePreflight

Notes

• The package is intentionally focused on runtime styling rather than becoming a full design-system framework.
• The public API is kept lean so it stays predictable and easy to adopt.

---

useTwSlots(config, props, deps?)

React hook for dynamic per-slot resolution. Same config shape as createTwSlots, but reactive.

import { useTwSlots } from 'twx-react';

function Modal({ size, children }) {
  const slots = useTwSlots({
    slots: {
      overlay: 'fixed inset-0 bg-black/50',
      content: 'bg-white rounded-xl shadow-xl',
      header: 'px-6 py-4 border-b',
      body: 'px-6 py-4',
    },
    variants: {
      size: {
        sm: { content: 'max-w-sm' },
        md: { content: 'max-w-md' },
        lg: { content: 'max-w-lg' },
      },
    },
  }, { size }, [size]);

  return (
    <div className={slots.overlay}>
      <div className={slots.content}>
        <div className={slots.header}>Modal Title</div>
        <div className={slots.body}>{children}</div>
      </div>
    </div>
  );
}

---

TypeScript

All APIs provide full type inference. Variant props are automatically derived from your config.

const Button = createTwComponent('button', {
  base: 'px-4 py-2 rounded',
  variants: {
    size: { sm: 'text-sm', md: 'text-base', lg: 'text-lg' },
    color: { primary: 'bg-blue-500', danger: 'bg-red-500' },
  },
});

// TypeScript knows: size?: 'sm' | 'md' | 'lg', color?: 'primary' | 'danger'
<Button size="sm" color="primary">OK</Button>

// Error: Type '"xl"' is not assignable to type '"sm" | "md" | "lg"'
<Button size="xl">Nope</Button>

Exported types:

import type {
  TwComponentConfig,
  TwComponentProps,
  TwComponent,
  VariantProps,
  CompoundVariant,
} from 'twx-react';

---

Performance

• LRU Cache — Generated CSS is cached (500+ entries) to avoid repeat parsing
• Memoization — Hooks use React.useMemo with configurable dependency arrays
• Pre-injection — createTwComponent injects all variant CSS at factory time, not render time
• Deduplication — The injector skips CSS rules that already exist in the stylesheet
• Tree-shakeable — Only import what you use; unused APIs are eliminated by bundlers

---

Comparison

Feature	twx-react	Tailwind Variants	CVA	Stitches
Runtime CSS	Yes	No (needs Tailwind)	No (needs Tailwind)	Yes
Zero config	Yes	No (PostCSS)	No (PostCSS)	Yes
Type-safe variants	Yes	Yes	Yes	Yes
Compound components	Yes	No	No	No
Multi-slot	Yes	Yes	No	No
Polymorphic as	Yes	No	No	Yes
React hooks	Yes	No	No	No
Bundle (min+gz)	~16KB	~3KB*	~1KB*	~8KB

* Tailwind Variants and CVA require the Tailwind CSS build toolchain separately.

---

License

MIT