LLMChain

You can use the existing LLMChain in a very similar way to before - provide a prompt and a model.

import { ChatOpenAI } from "langchain/chat_models/openai";
import { LLMChain } from "langchain/chains";
import { ChatPromptTemplate } from "langchain/prompts";

const template =
  "You are a helpful assistant that translates {input_language} to {output_language}.";
const humanTemplate = "{text}";

const chatPrompt = ChatPromptTemplate.fromMessages([
  ["system", template],
  ["human", humanTemplate],
]);

const chat = new ChatOpenAI({
  temperature: 0,
});

const chain = new LLMChain({
  llm: chat,
  prompt: chatPrompt,
});

const result = await chain.call({
  input_language: "English",
  output_language: "French",
  text: "I love programming",
});

// { text: "J'adore programmer" }