IndexedDB Vector Store for LangChain

A LangChain compatible vector store implementation using IndexedDB for browser-based applications.

Features

• 🚀 Compatible with LangChain's vector store interface
• 💾 Browser-based storage using IndexedDB
• 🔍 Support for metadata filtering
• ⚡ Efficient similarity search
• 📦 Zero dependencies (except for LangChain and Dexie)

Installation

npm install indexed-db-vector-store

Usage

import { IndexedDBLangChainVectorStore } from 'indexed-db-vector-store';
import { OpenAIEmbeddings } from 'langchain/embeddings/openai';

// Initialize the vector store
const vectorStore = new IndexedDBLangChainVectorStore({
  embeddings: new OpenAIEmbeddings(),
  dbName: 'my-vector-store',
  tableName: 'documents'
});

// Add documents
await vectorStore.addDocuments([
  { pageContent: 'Hello world', metadata: { source: 'test' } }
]);

// Search for similar documents
const results = await vectorStore.similaritySearch('Hello', 1);
console.log(results);

API Reference

Constructor

new IndexedDBLangChainVectorStore({
  embeddings: EmbeddingsInterface,
  dbName: string,
  tableName: string,
  metadata?: Record<string, any>
})

Methods

• addDocuments(documents: Document[]): Promise<void>
• addVectors(vectors: number[][], documents: Document[]): Promise<void>
• similaritySearch(query: string, k: number, filter?: Record<string, any>): Promise<Document[]>
• similaritySearchVectorWithScore(query: number[], k: number, filter?: Record<string, any>): Promise<[Document, number][]>

Development

# Install dependencies
npm install

# Build the package
npm run build

# Run tests
npm test

License

MIT License

Copyright (c) 2025 Ushida Yosei

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.