@langchain/community/dist/vectorstores/lancedb.js

Third-party integrations for LangChain.js

import { __export } from "../_virtual/rolldown_runtime.js";
import { Document } from "@langchain/core/documents";
import { VectorStore } from "@langchain/core/vectorstores";
import { connect } from "@lancedb/lancedb";

//#region src/vectorstores/lancedb.ts
var lancedb_exports = {};
__export(lancedb_exports, { LanceDB: () => LanceDB });
/**
* A wrapper for an open-source database for vector-search with persistent
* storage. It simplifies retrieval, filtering, and management of
* embeddings.
*/
var LanceDB = class LanceDB extends VectorStore {
	table;
	textKey;
	uri;
	tableName;
	mode;
	constructor(embeddings, args) {
		super(embeddings, args || {});
		this.table = args?.table;
		this.embeddings = embeddings;
		this.textKey = args?.textKey || "text";
		this.uri = args?.uri || "~/lancedb";
		this.tableName = args?.tableName || "langchain";
		this.mode = args?.mode || "overwrite";
	}
	/**
	* Adds documents to the database.
	* @param documents The documents to be added.
	* @returns A Promise that resolves when the documents have been added.
	*/
	async addDocuments(documents) {
		const texts = documents.map(({ pageContent }) => pageContent);
		return this.addVectors(await this.embeddings.embedDocuments(texts), documents);
	}
	_vectorstoreType() {
		return "lancedb";
	}
	/**
	* Adds vectors and their corresponding documents to the database.
	* @param vectors The vectors to be added.
	* @param documents The corresponding documents to be added.
	* @returns A Promise that resolves when the vectors and documents have been added.
	*/
	async addVectors(vectors, documents) {
		if (vectors.length === 0) return;
		if (vectors.length !== documents.length) throw new Error(`Vectors and documents must have the same length`);
		const data = [];
		for (let i = 0; i < documents.length; i += 1) {
			const record = {
				vector: vectors[i],
				[this.textKey]: documents[i].pageContent
			};
			Object.keys(documents[i].metadata).forEach((metaKey) => {
				record[metaKey] = documents[i].metadata[metaKey];
			});
			data.push(record);
		}
		if (!this.table) {
			const db = await connect(this.uri);
			this.table = await db.createTable(this.tableName, data, { mode: this.mode });
			return;
		}
		await this.table.add(data);
	}
	/**
	* Performs a similarity search in the database and returns
	* the documents.
	* @param query The query string.
	* @param k The number of results to return.
	* @returns A Promise that resolves with an array, each containing a Document.
	*/
	async similaritySearch(query, k) {
		const results = await this.similaritySearchWithScore(query, k);
		return results.map((result) => result[0]);
	}
	/**
	* Performs a similarity search in the database and returns
	* the documents and their scores.
	* @param query The query string.
	* @param k The number of results to return.
	* @returns A Promise that resolves with an array of tuples, each containing a Document and its score.
	*/
	async similaritySearchWithScore(query, k) {
		const queryEmbedding = await this.embeddings.embedQuery(query);
		return this.similaritySearchVectorWithScore(queryEmbedding, k);
	}
	/**
	* Performs a similarity search on the vectors in the database and returns
	* the documents and their scores.
	* @param query The query vector.
	* @param k The number of results to return.
	* @returns A Promise that resolves with an array of tuples, each containing a Document and its score.
	*/
	async similaritySearchVectorWithScore(query, k) {
		if (!this.table) throw new Error("Table not found. Please add vectors to the table first.");
		const results = await this.table.query().nearestTo(query).limit(k).toArray();
		const docsAndScore = [];
		results.forEach((item) => {
			const metadata = {};
			Object.keys(item).forEach((key) => {
				if (key !== "vector" && key !== "score" && key !== this.textKey) metadata[key] = item[key];
			});
			docsAndScore.push([new Document({
				pageContent: item[this.textKey],
				metadata
			}), item.score]);
		});
		return docsAndScore;
	}
	/**
	* Creates a new instance of LanceDB from texts.
	* @param texts The texts to be converted into documents.
	* @param metadatas The metadata for the texts.
	* @param embeddings The embeddings to be managed.
	* @param dbConfig The configuration for the LanceDB instance.
	* @returns A Promise that resolves with a new instance of LanceDB.
	*/
	static async fromTexts(texts, metadatas, embeddings, dbConfig) {
		const docs = [];
		for (let i = 0; i < texts.length; i += 1) {
			const metadata = Array.isArray(metadatas) ? metadatas[i] : metadatas;
			const newDoc = new Document({
				pageContent: texts[i],
				metadata
			});
			docs.push(newDoc);
		}
		return LanceDB.fromDocuments(docs, embeddings, dbConfig);
	}
	/**
	* Creates a new instance of LanceDB from documents.
	* @param docs The documents to be added to the database.
	* @param embeddings The embeddings to be managed.
	* @param dbConfig The configuration for the LanceDB instance.
	* @returns A Promise that resolves with a new instance of LanceDB.
	*/
	static async fromDocuments(docs, embeddings, dbConfig) {
		const instance = new this(embeddings, dbConfig);
		await instance.addDocuments(docs);
		return instance;
	}
};

//#endregion
export { LanceDB, lancedb_exports };
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