Fenix Store

Lightweight • Reactive • Zero Dependencies • TypeScript

A tiny but powerful state management library for JavaScript applications. It provides a reactive API to manage the state of your application.

Why?

After some years dealing with other complex solutions I decided to create this library with the following principles:

• Reactive: It allows you to subscribe to changes in the state of your application.
• Simple: It's designed to be simple and easy to use.
• Flexible: It allows you to create side effects and middleware to apply and listen to changes.
• Lightweight: It's small (1.8kb gzipped), with no dependencies.
• Type-Safe: Full TypeScript support with strict type checking.

Installation

Install with npm:

  npm install fenix-store

or with yarn:

  yarn add fenix-store

Usage

import { FenixStore } from 'fenix-store';

const store = FenixStore.create();
console.log(store.get());
// {}

store.on('user.name').set('John Doe');

console.log(store.on('user.name').get());
// 'John Doe'

console.log(store.get());
// { user: { name: 'John Doe' } }

Subscribe / Unsubscribe:

...

const unsubscribe = store
  .on('user.name')
  .subscribe(console.log);

store
  .on('user.name')
  .set('John Doe'); // 'John Doe'

unsubscribe();

store
  .on('user.name')
  .set('Jane Doe'); // nothing

Side Effects / Middleware

...

store
  .effects
  .use(
    // Return an object with the 'next' property to change the value, otherwise no changes will be applied.
    (path, next) => {
      if (path !== 'user.name') return;

      return { next: `Hello, ${next}` };
    },
  )

store
  .on('user.name')
  .subscribe(console.log);

store
  .on('user.name')
  .set('John Doe');
  // 'Hello, John Doe'

store
  .on('user.name')
  .set('Jane Doe');
  // 'Hello, Jane Doe'

...

const changeStack = [];

store
  .effects
  .use(
    (path, next, previous) => {
      changeStack.push({
        path,
        next,
        previous,
      });
    },
  );

store
  .on('user.name')
  .set('John Doe');

store
  .on('user.name')
  .set('Jane Doe');

console.log(changeStack.at(-1));
// { path: 'user.name', next: 'Jane Doe', previous: 'John Doe' }

🔧 Development

Quick Start

# Install dependencies
pnpm install

# Run tests in watch mode
pnpm dev

# Build the library
pnpm build

Quality Assurance

• ✅ TypeScript strict type checking
• ✅ ESLint code quality analysis
• ✅ Comprehensive test coverage
• ✅ Bundle size monitoring
• ✅ Security vulnerability scanning

CI/CD Pipeline

The project uses GitHub Actions for:

• Continuous Integration: Automated testing on code pushes (Node.js 18, 20, 21)
• Bundle Monitoring: Size tracking and analysis
• Quality Gates: Code quality and security checks
• Release Automation: Streamlined publishing with bundle metrics

🤝 Contributing

This library is designed to be lightweight and focused, but contributions are welcome!

Quick Start

pnpm install && pnpm dev    # Install deps + run tests in watch mode

Before Submitting a PR

• Ensure tests pass: pnpm test
• Check bundle size impact: pnpm size:check
• Keep changes focused and well-documented

The CI pipeline will automatically validate code quality, run tests across multiple Node.js versions, and provide bundle size feedback.

📈 Project Status

This project follows a stability-first approach with careful consideration for changes to maintain its lightweight nature and zero-dependency philosophy.

• Bundle Size: 1.8KB gzipped (target: <3KB) ✅
• Test Coverage: Comprehensive test suite ✅
• TypeScript: Strict mode with full type safety ✅
• Dependencies: Zero runtime dependencies ✅
• CI/CD: Fully automated quality pipeline ✅

License: MIT