🌪️ Zephyr Events

Ultra-fast ES2023 event emitter with 905B bundle size and race-condition safety.

⚡ Key Features

• 🔥 Ultra Fast: 33M+ operations/second with native Set/Map optimizations
• 🪶 Tiny Bundle: Only 905B minified, 0 dependencies
• 🛡️ Race-Condition Safe: Immutable snapshots prevent handler modification issues
• 🎯 ES2023 Native: Optional chaining, nullish coalescing, spread operators
• 📦 Tree Shakeable: ES modules with proper exports
• 🔧 TypeScript: Full type safety with generics and strict types

📥 Installation

npm install zephyr-events

🚀 Quick Start

import zephyrEvents from 'zephyr-events';

// Create typed emitter
type Events = {
  user: { id: number; name: string }
  error: Error
}

const emitter = zephyrEvents<Events>();

// Subscribe with auto-cleanup
const unsubscribe = emitter.on('user', (user) => {
  console.log(`User: ${user.name}`);
});

// Emit events
emitter.emit('user', { id: 1, name: 'Alice' });

// Cleanup
unsubscribe();

🎨 API Reference

zephyrEvents<Events>()

Create a new event emitter instance.

const emitter = zephyrEvents<{
  message: string
  data: { value: number }
}>();

emitter.on(type, handler)

Register event handler. Returns unsubscribe function.

const unsub = emitter.on('message', (msg) => {
  console.log(msg);
});

// Wildcard listener
emitter.on('*', (type, event) => {
  console.log(`Event ${type}:`, event);
});

emitter.off(type, handler?)

Remove event handler(s).

// Remove specific handler
emitter.off('message', handler);

// Remove all handlers for type
emitter.off('message');

emitter.emit(type, event)

Emit event to all registered handlers.

emitter.emit('message', 'Hello World!');
emitter.emit('data', { value: 42 });

🏗️ Technical Details

Architecture

Zephyr Events uses a dual-storage architecture for maximum performance:

• Set: O(1) add/remove operations
• Array snapshots: Fast iteration with race-condition safety
• ES2023 optimizations: Native optional chaining and nullish coalescing

Race-Condition Safety

Handlers are executed from immutable snapshots:

emitter.on('test', function selfRemover() {
  emitter.off('test', selfRemover); // Safe during emit
});

ES2023 Features

• Nullish coalescing: all ??= new Map()
• Optional chaining: handlers?.size
• Spread operators: [...handlers] for fast snapshots

Bundle Formats

• ESM: dist/zephyr-events.mjs (905B)
• CommonJS: dist/zephyr-events.js (977B)
• UMD: dist/zephyr-events.umd.js (1.3KB)

🆚 Comparison

| Feature | Zephyr Events | mitt* | eventemitter3 | |---------|---------------|------|---------------| | Bundle Size | 905B | 200B | 7KB | | TypeScript | ✅ Native | ✅ | ✅ | | Race-Safe | ✅ | ❌ | ❌ | | ES2023 | ✅ | ❌ | ❌ | | Performance | 33M ops/s | 15M ops/s | 10M ops/s |

*Based on original mitt package by Jason Miller

🚀 Performance Benchmarks

Comprehensive performance benchmarks on Apple Silicon M-series (ARM64) with Node.js v23.10.0:

Core Operations Performance

| Operation | Ops/Second | Description | |-----------|------------|-------------| | Emitter Creation | 10.54M | Creating new emitter instances | | Single Handler Emit | 33.69M | Emitting to one event handler | | Wildcard Emit | 26.12M | Emitting to wildcard listeners | | 10 Handlers Emit | 9.32M | Emitting to 10 concurrent handlers | | 100 Handlers Emit | 1.57M | Emitting to 100 concurrent handlers | | Mixed Operations | 7.17M | Realistic usage: on/emit/off cycle |

Management Operations Performance

| Operation | Ops/Second | Description | |-----------|------------|-------------| | Off Method | 194.17M | Removing specific handler with .off() | | Unsubscribe | 143.54M | Removing handler with returned function | | Event Subscription | 9.19K | Adding new event handlers with .on() | | Memory Stress | 130 | Complex multi-event scenario |

Key Performance Insights

• 🔥 Ultra-fast emission: Up to 33.69M operations/second for single handlers
• ⚡ Instant cleanup: Handler removal at 194.17M operations/second
• 📈 Scales efficiently: Maintains high performance with multiple handlers
• 🛡️ Race-condition safe: Minimal overhead for safety guarantees
• 🎯 Real-world optimized: 7.17M ops/sec for typical usage patterns

Architecture Benefits

• Dual Storage: Set for O(1) add/remove + Array snapshots for fast iteration
• ES2023 Native: Optional chaining (?.) and nullish coalescing (??) optimizations
• Memory Efficient: Stable performance under stress conditions
• Zero Dependencies: Pure JavaScript with no external overhead

🙏 Acknowledgments

Zephyr Events is a heavy modernization and performance upgrade of the original mitt package by Jason Miller. Thanks for the foundational work!

🤝 Contributing

Contributions welcome! Please read CONTRIBUTING.md.

📄 License

MIT © ebogdum

Original mitt: MIT © Jason Miller