Expressive MVC

Define reactive UI with plain classes. When properties change, your components will too.

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Expressive puts application state, behavior, and lifecycle in plain classes. Class fields are reactive, getters are computed, methods are auto-bound, and UI components subscribe only to the values they read.

Install

npm install @expressive/react

Quick start

import State from '@expressive/react';
class Counter extends State {
  count = 0;
increment() {
    this.count++;
  }
decrement() {
    this.count--;
  }
}
function CounterWidget() {
  const { count, increment, decrement } = Counter.use();
return (
    <div>
      <button onClick={decrement}>-</button>
      <span>{count}</span>
      <button onClick={increment}>+</button>
    </div>
  );
}

No reducers, selectors, dependency arrays, or action wrappers. Update a property and every consumer that reads it updates automatically.

The adapter is renderer-agnostic, so the same install covers React Native and Expo - exercised on an iOS simulator and an Android emulator in both Debug and Release builds (Expo SDK 57, React Native 0.86) and gated per release on Metro resolution and a Hermes build. See React Native for the three boundaries.

Continue with Getting Started, explore the guides, or browse the API reference.

Packages

| Package | Description | | --- | --- | | @expressive/mvc | Framework-agnostic reactive core and component model. Comes with the adapter - install directly only for host-agnostic code. | | @expressive/react | React adapter and the recommended entry point for React applications. The only package a React app installs. | | @expressive/router | Host-agnostic router built on Expressive components. The newest package, and the one that moves the most. |

All packages are pre-1.0 under one discipline: breaking changes land only in minor versions, each documented by a changeset in the package's CHANGELOG - patch releases are always safe to take.

Learn more

• Why classes?
• Design decisions
• Migrating from hooks
• Comparisons with other state libraries
• Live examples
• Using Expressive with a coding agent

Contributing

This repository is a Bun workspace. To get started:

bun install
bun run test
bun run build

See AGENTS.md for repository conventions and .github/RELEASING.md for the release process.

License

MIT