import { MemoryVectorStore } from "langchain/vectorstores/memory";
import { OpenAIEmbeddings } from "langchain/embeddings/openai";
import { similarity } from "ml-distance";

const vectorStore = await MemoryVectorStore.fromTexts(
  ["Hello world", "Bye bye", "hello nice world"],
  [{ id: 2 }, { id: 1 }, { id: 3 }],
  new OpenAIEmbeddings(),
  { similarity: similarity.pearson }
);

const resultOne = await vectorStore.similaritySearch("hello world", 1);
console.log(resultOne);