Class SimpleSequentialChain

Deprecated

Switch to expression language: https://js.langchain.com/docs/expression_language/ Simple chain where a single string output of one chain is fed directly into the next.

Example

import { SimpleSequentialChain, LLMChain } from "langchain/chains";
import { OpenAI } from "langchain/llms/openai";
import { PromptTemplate } from "langchain/prompts";

// This is an LLMChain to write a synopsis given a title of a play.
const llm = new OpenAI({ temperature: 0 });
const template = `You are a playwright. Given the title of play, it is your job to write a synopsis for that title.

Title: {title}
Playwright: This is a synopsis for the above play:`
const promptTemplate = new PromptTemplate({ template, inputVariables: ["title"] });
const synopsisChain = new LLMChain({ llm, prompt: promptTemplate });


// This is an LLMChain to write a review of a play given a synopsis.
const reviewLLM = new OpenAI({ temperature: 0 })
const reviewTemplate = `You are a play critic from the New York Times. Given the synopsis of play, it is your job to write a review for that play.

Play Synopsis:
{synopsis}
Review from a New York Times play critic of the above play:`
const reviewPromptTemplate = new PromptTemplate({ template: reviewTemplate, inputVariables: ["synopsis"] });
const reviewChain = new LLMChain({ llm: reviewLLM, prompt: reviewPromptTemplate });

const overallChain = new SimpleSequentialChain({chains: [synopsisChain, reviewChain], verbose:true})
const review = await overallChain.run("Tragedy at sunset on the beach")
// the variable review contains resulting play review.
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