# AppRun

## News

We just released AppRun 3.36.0. See whats new for details.

In this release we had a code review by using Copilot and Claude Sonnet 4, which found and fixed minor bugs and edge cases in virtual DOM handling, as well as bugs in router initialization logic. Also improved overall code quality and stability.

## Introduction

AppRun is a lightweight alternative to other frameworks and libraries. It has a unique architecture inspired by the Elm architecture that can help you manage states, routing, and other essential aspects of your web application.

Use a Counter as an example.

    // define the initial state
    const state = 0;

    // view is a function to display the state (JSX)
    const view = state => <div>
      <h1>{state}</h1>
      <button onclick="app.run('-1')">-1</button>
      <button onclick="app.run('+1')">+1</button>
    </div>;

    // update is a collection of event handlers
    const update = {
      '+1': state => state + 1,
      '-1': state => state - 1
    };

    // start the app
    app.start(document.body, state, view, update);

- AppRun is lightweight, only 6KB gzipped, but includes state management, rendering, event handling, and routing.

- With only three functions: `app.start`, `app.run`, and `app.on` in its API makes it easy to learn and use. And no worries about the incompatibility of version upgrades.

- One more thing, you can use AppRun with React to simplify state management and routing of your React applications.

At its core, AppRun harnesses the power of the event PubsSub pattern to streamline your application’s state handling and routing. The result? Cleaner, more maintainable code and a smoother development experience.

## AppRun Benefits

- Clean architecture that needs less code
- State management and routing included
- No proprietary syntax to learn (no hooks, no reducers, no signals)
- Use directly in the browser or with a compiler/bundler
- Advanced features: JSX, Web Components, Dev Tools, SSR, etc.

## Getting Started

AppRun is distributed on npm. To get it, run:

    npm install apprun

You can also load AppRun directly from the unpkg.com CDN:

    <html>
    <body>
    <script src="https://unpkg.com/apprun/dist/apprun-html.js"></script>
    <script>
      const view = state => `<div>${state}</div>`;
      app.start(document.body, 'hello AppRun', view);
    </script>
    </body>
    </html>

Or, use the ESM version:

    <html>
    <body>
    <script type="module">
      import { app, html } from 'https://unpkg.com/apprun/dist/apprun-html.esm.js';
      const view = state => html`<div>${state}</div>`;
      app.start(document.body, 'hello ESM', view);
    </script>
    </body>
    </html>

In addition to run directly in the browser, or with a compiler/bundler like Webpack or Vite.

You can run the `npm create apprun-app` command to create an AppRun project.

    npm create apprun-app [my-app]

### Learn More

You can get started with AppRun Docs and the AppRun Playground.

### AppRun Book from Apress

- Order from Amazon

## Contribute

You can launch the webpack dev-server and the demo app from the demo folder with the following npm commands:

    npm install
    npm start

You can run the unit tests from the tests folder.

    npm test

Unit tests can serve as functional specifications.

Finally, to build optimized js files to the dist folder, just run:

    npm run build

Have fun and send pull requests.

## Contributors

## Support

AppRun is an MIT-licensed open-source project. Please consider supporting the project on Patreon. 👍❤️🙏

### Thank you for your support

- Athkahden Asura
- Alfred Nerstu
- Gyuri Lajos
- Lorenz Glißmann
- Kevin Shi
- Chancy Kennedy

## License

MIT

Copyright (c) 2015-2025 Yiyi Sun