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.

Hierarchy (view full)

Implements

Constructors

constructor

Properties

chains inputKey outputKey trimOutputs memory?

Accessors

inputKeys outputKeys

Methods

apply call invoke prepOutputs run serialize deserialize

Constructors

constructor

Properties

chains

chains: BaseChain<ChainValues, ChainValues>[]

Array of chains to run as a sequence. The chains are run in order they appear in the array.

inputKey

inputKey: string = "input"

outputKey

outputKey: string = "output"

trimOutputs

trimOutputs: boolean

Whether or not to trim the intermediate outputs.

Optional memory

memory?: BaseMemory

Accessors

inputKeys

outputKeys

Methods

apply

  • apply(inputs, config?): Promise<ChainValues[]>

  • Parameters

    • inputs: ChainValues[]
    • Optional config: (RunnableConfig | CallbackManager | (BaseCallbackHandler | BaseCallbackHandlerMethodsClass)[])[]

    Returns Promise<ChainValues[]>

    ⚠️ Deprecated ⚠️

    Use .batch() instead. Will be removed in 0.2.0.

    This feature is deprecated and will be removed in the future.

    It is not recommended for use.

    Call the chain on all inputs in the list

call

  • call(values, config?, tags?): Promise<ChainValues>

  • Parameters

    • values: ChainValues & {
          signal?: AbortSignal;
          timeout?: number;
      }
    • Optional config: RunnableConfig | CallbackManager | (BaseCallbackHandler | BaseCallbackHandlerMethodsClass)[]
    • Optional tags: string[]

      Deprecated

    Returns Promise<ChainValues>

    Deprecated

    Use .invoke() instead. Will be removed in 0.2.0.

    Run the core logic of this chain and add to output if desired.

    Wraps _call and handles memory.

invoke

  • invoke(input, options?): Promise<ChainValues>

  • Invoke the chain with the provided input and returns the output.

    Parameters

    • input: ChainValues

      Input values for the chain run.

    • Optional options: RunnableConfig

    Returns Promise<ChainValues>

    Promise that resolves with the output of the chain run.

prepOutputs

  • prepOutputs(inputs, outputs, returnOnlyOutputs?): Promise<Record<string, unknown>>

  • Parameters

    • inputs: Record<string, unknown>
    • outputs: Record<string, unknown>
    • returnOnlyOutputs: boolean = false

    Returns Promise<Record<string, unknown>>

run

  • run(input, config?): Promise<string>

  • Parameters

    • input: any
    • Optional config: RunnableConfig | CallbackManager | (BaseCallbackHandler | BaseCallbackHandlerMethodsClass)[]

    Returns Promise<string>

    Deprecated

    Use .invoke() instead. Will be removed in 0.2.0.

serialize

Static deserialize

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