bun-pageindex

Bun-native vectorless, reasoning-based RAG for document understanding. A TypeScript port of PageIndex optimized for the Bun runtime.

Features

• Vectorless RAG: Uses LLM reasoning to build hierarchical document indices without vector databases
• PDF Support: Extract structure and content from PDF documents
• OCR Mode: Process scanned PDFs using GLM-OCR vision model (not in original PageIndex!)
• Markdown Support: Convert markdown documents to tree structures
• LLM Agnostic: Works with OpenAI, LM Studio, Ollama, or any OpenAI-compatible API
• Bun Native: Optimized for Bun runtime with minimal dependencies
• CLI & API: Use as a library or command-line tool

Installation

bun add bun-pageindex

For OCR Mode (Scanned PDFs)

OCR mode requires Poppler to be installed on your system:

# macOS
brew install poppler

# Ubuntu/Debian
sudo apt-get install poppler-utils

# Windows
# Download from https://github.com/oschwartz10612/poppler-windows/releases

Quick Start

As a Library

import { PageIndex, indexPdf, mdToTree } from "bun-pageindex";

// Process a PDF with OpenAI
const result = await indexPdf("document.pdf", {
  apiKey: process.env.OPENAI_API_KEY,
  model: "gpt-4o",
});

console.log(result.structure);

// Or use the PageIndex class for more control
const pageIndex = new PageIndex({
  model: "gpt-4o",
  addNodeSummary: true,
  addDocDescription: true,
});

const pdfResult = await pageIndex.fromPdf("document.pdf");

// Process markdown
const mdResult = await mdToTree("document.md", {
  addNodeSummary: true,
  thinning: true,
  thinningThreshold: 5000,
});

Using LM Studio (Local LLMs)

import { PageIndex } from "bun-pageindex";

const pageIndex = new PageIndex({
  model: "local-model", // Your LM Studio model name
}).useLMStudio();

const result = await pageIndex.fromPdf("document.pdf");

Using Ollama

import { PageIndex } from "bun-pageindex";

const pageIndex = new PageIndex({
  model: "llama3",
}).useOllama();

const result = await pageIndex.fromPdf("document.pdf");

OCR Mode for Scanned PDFs

OCR mode converts PDF pages to images and uses a vision model (like GLM-OCR) to extract text, then processes with a reasoning model.

import { PageIndex, indexPdfWithOcr, indexPdfWithLMStudioOcr } from "bun-pageindex";

// Using OpenAI
const result = await indexPdfWithOcr("scanned-document.pdf", {
  apiKey: process.env.OPENAI_API_KEY,
  reasoningModel: "gpt-4o",
  ocrModel: "gpt-4o", // OpenAI vision model
});

// Using LM Studio with local models
const result = await indexPdfWithLMStudioOcr(
  "scanned-document.pdf",
  "qwen/qwen3-vl-30b",           // Reasoning model
  "mlx-community/GLM-OCR-bf16"   // OCR vision model
);

// Or use the PageIndex class directly
const pageIndex = new PageIndex({
  model: "qwen/qwen3-vl-30b",
  extractionMode: "ocr",
  ocrModel: "mlx-community/GLM-OCR-bf16",
  imageDpi: 150,
}).useLMStudio();

const result = await pageIndex.fromPdf("scanned-document.pdf");

CLI Usage

# Process a PDF
bun-pageindex --pdf document.pdf

# Process with LM Studio
bun-pageindex --pdf document.pdf --lmstudio --model llama3

# Process scanned PDF with OCR
bun-pageindex --pdf scanned.pdf --ocr --lmstudio --model qwen/qwen3-vl-30b

# Process markdown with options
bun-pageindex --md README.md --add-doc-description --thinning

# See all options
bun-pageindex --help

API Reference

PageIndex Class

const pageIndex = new PageIndex(options);

Options:

• model: LLM model to use (default: "gpt-4o-2024-11-20")
• apiKey: OpenAI API key (default: from OPENAI_API_KEY env var)
• baseUrl: Custom API base URL (for LM Studio, Ollama, etc.)
• tocCheckPageNum: Pages to check for TOC (default: 20)
• maxPageNumEachNode: Max pages per node (default: 10)
• maxTokenNumEachNode: Max tokens per node (default: 20000)
• addNodeId: Add node IDs (default: true)
• addNodeSummary: Generate summaries (default: true)
• addDocDescription: Add document description (default: false)
• addNodeText: Include raw text (default: false)

OCR Options:

• extractionMode: "text" (default) or "ocr" for scanned PDFs
• ocrModel: Vision model for OCR (default: "mlx-community/GLM-OCR-bf16")
• ocrPromptType: "text", "formula", or "table" (default: "text")
• imageDpi: DPI for PDF to image conversion (default: 150)
• imageFormat: "png" or "jpeg" (default: "png")
• ocrConcurrency: Concurrent OCR requests (default: 3)

Methods:

• fromPdf(input): Process a PDF file or buffer
• useLMStudio(): Configure for LM Studio
• useOllama(): Configure for Ollama
• useOcrMode(ocrModel?): Enable OCR mode
• setBaseUrl(url): Set custom API base URL

mdToTree Function

const result = await mdToTree(path, options);

Additional Options:

• thinning: Apply tree thinning (default: false)
• thinningThreshold: Min tokens for thinning (default: 5000)
• summaryTokenThreshold: Token threshold for summaries (default: 200)

Result Structure

interface PageIndexResult {
  docName: string;
  docDescription?: string;
  structure: TreeNode[];
}

interface TreeNode {
  title: string;
  nodeId?: string;
  startIndex?: number;
  endIndex?: number;
  summary?: string;
  prefixSummary?: string;
  text?: string;
  lineNum?: number;
  nodes?: TreeNode[];
}

Benchmarks

Run benchmarks comparing Bun vs Python implementations:

# Requires LM Studio running on localhost:1234
bun run benchmark

Development

# Install dependencies
bun install

# Run tests
bun test

# Build
bun run build

How It Works

PageIndex uses LLM reasoning to:

1. Detect Table of Contents: Scans initial pages for TOC
2. Extract Structure: Parses TOC or generates structure from content
3. Map Page Numbers: Associates logical page numbers with physical pages
4. Build Tree: Creates hierarchical tree structure
5. Generate Summaries: Creates summaries for each node (optional)

This approach provides human-like document understanding without the limitations of vector-based retrieval.

OCR Mode (New in bun-pageindex)

For scanned PDFs, OCR mode adds an additional step:

1. Convert PDF to Images: Uses Poppler to render each page as an image
2. OCR Extraction: Uses a vision model (GLM-OCR) to extract text from images
3. Standard Processing: Continues with the same reasoning-based indexing

This enables processing of scanned documents that the original Python PageIndex cannot handle.

Credits

This is a Bun/TypeScript port of PageIndex by VectifyAI.

License

MIT

Author

Antonio Oliveira antonio@oakoliver.com (oakoliver.com)