Delta SDK

A high-performance, developer-friendly Node.js and Browser SDK for tracking delta variables.

Perfect for systems that need to react to how much a value changed and how fast, such as reactive music visuals, game loops, sensor streams, and financial tickers.

🚀 Features

• Blazing Fast: Designed for high-frequency updates (up to 1,000,000+ per second).
• Reactive: Subscribe to updates or set custom thresholds.
• Smart Metrics: Instant access to delta, absolute delta, percent change, direction, and velocity.
• Signal Processing: Built-in exponential smoothing for noisy sensor data.
• History & Snapshots: Optional history buffers for time-series analysis.
• Zero Dependencies: Pure JavaScript, ESM-first, and tiny footprint.

📦 Installation

npm install delta-sdk

🛠 Quick Start

Basic Tracking

import { createDeltaVariable } from 'delta-sdk';

const speed = createDeltaVariable({ name: 'speed', initialValue: 0 });

speed.update(10);
speed.update(15);

console.log(speed.delta());     // 5
console.log(speed.direction()); // 'up'
console.log(speed.snapshot()); 

Managing Multiple Streams

import { createDeltaManager } from 'delta-sdk';

const deltas = createDeltaManager();
deltas.create('volume', 0.2);
deltas.create('bass', 0.1);

deltas.batchUpdate({ volume: 0.8, bass: 0.9 });
console.log(deltas.snapshotAll());

🎨 Interactive Demo

Check out the /examples/web-visualizer folder for a real-time Music Visualizer.

1. Open index.html.
2. Drop an MP3 file.
3. Watch the Delta SDK drive the visuals in real-time based on volume jumps and bass hits.

📖 Documentation

Full documentation is available in the /docs folder:

• What are Deltas?
• API Guide
• Examples Explained

🔧 Configuration Options

| Option | Type | Default | Description | |---|---|---|---| | name | string | 'unnamed' | Label for the variable. | | initialValue | number | 0 | Starting baseline. | | smoothing | boolean | false | Enable exponential moving average. | | smoothingFactor | number | 0.2 | 0-1 range (lower = smoother). | | keepHistory | boolean | false | Store previous snapshots in a buffer. | | historyLimit | number | 100 | Max snapshots to keep. | | thresholds | object | {} | Define trigger points for absDelta, delta, etc. |

🧪 Testing

npm test

📈 Benchmarks

npm run bench

📄 License

MIT © Leumas Tech