LOON (LLM Optimised Object Notations)

LOON is an encoder-only library that reduces token consumption by ~40-50% compared to minified JSON. It's designed specifically for LLM communication where every token counts.

The format removes unnecessary syntax, uses unquoted strings where safe, and employs schema optimization for arrays – all while remaining readable enough for LLMs to understand naturally.

Installation

npm install @atishhamte/loon

Usage

import { encode } from '@atishhamte/loon';

// Encode JavaScript data to LOON format
const data = {
  users: [
    { id: 1, name: 'Alice', role: 'admin' },
    { id: 2, name: 'Bob', role: 'user' },
    { id: 3, name: 'Charlie', role: 'user' },
  ],
};

const loon = encode(data);
console.log(loon);
// {users:[{id,name,role}:1,Alice,admin;2,Bob,user;3,Charlie,user]}

With LLMs

import { encode } from 'loon';

const context = {
  conversation: [
    { role: 'user', message: 'What is the weather?' },
    { role: 'assistant', message: 'It is sunny today.' },
  ],
  settings: { temperature: 0.7, maxTokens: 150 },
};

const prompt = `Context: ${encode(context)}\n\nQuestion: Summarize the conversation.`;
// Send to LLM...

Format Comparison

Example: User Data

JSON (formatted):

{
  "users": [
    { "id": 1, "name": "Alice", "role": "admin" },
    { "id": 2, "name": "Bob", "role": "user" },
    { "id": 3, "name": "Charlie", "role": "user" }
  ]
}

236 characters (includes newlines and spaces)

JSON.stringify (minified):

{
  "users": [
    { "id": 1, "name": "Alice", "role": "admin" },
    { "id": 2, "name": "Bob", "role": "user" },
    { "id": 3, "name": "Charlie", "role": "user" }
  ]
}

126 characters

TOON:

users[3]{id,name,role}:
  1,Alice,admin
  2,Bob,user
  3,Charlie,user

69 characters (45.2% vs minified)

LOON:

{users:[{id,name,role}:1,Alice,admin;2,Bob,user;3,Charlie,user]}

64 characters (49.2% vs minified) - Single line, better for LLMs

Benchmarks

| Data Type | JSON (formatted) | Minified | TOON | LOON | LOON Savings | | ----------------------- | ---------------- | ---------- | --------- | --------- | ------------ | | Simple objects | 236 chars | 126 chars | 69 chars | 64 chars | 49.2% ✓ | | API responses | 520 chars | 277 chars | 179 chars | 161 chars | 41.9% ✓ | | Database records | 414 chars | 293 chars | 186 chars | 176 chars | 39.9% ✓ | | Time series (5 items) | 547 chars | 325 chars | 149 chars | 139 chars | 57.2% ✓ | | Large arrays (20 items) | 1985 chars | 1384 chars | 750 chars | 707 chars | 48.9% ✓ | | Mixed data types | 192 chars | 122 chars | 109 chars | 100 chars | 18.0% ✓ |

Average: 42.5% compression vs minified JSON

LOON advantages:

✅ Single-line format (better for LLMs and APIs)

✅ 42.5% average compression vs minified JSON

✅ Handles mixed/nested structures efficiently

✅ No newlines (saves tokens)

API

encode(value: unknown): string

Encodes a JavaScript value into LOON format.

Example:

const data = { name: 'Alice', age: 30 };
const loon = encode(data);
// {name:Alice;age:30}

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines.

# Clone and setup
git clone https://github.com/YOUR_USERNAME/loon.git
cd loon
npm install

# Build
npm run build

# Lint and format
npm run lint
npm run format

License

MIT License © 2025-PRESENT

Questions or feedback? Open an issue on GitHub.