Class SequentialChain

Chain where the outputs of one chain feed directly into next.

Example

const promptTemplate = new PromptTemplate({
  template: `You are a playwright. Given the title of play and the era it is set in, it is your job to write a synopsis for that title.
Title: {title}
Era: {era}
Playwright: This is a synopsis for the above play:`,
  inputVariables: ["title", "era"],
});

const reviewPromptTemplate = new PromptTemplate({
  template: `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:`,
  inputVariables: ["synopsis"],
});

const overallChain = new SequentialChain({
  chains: [
    new LLMChain({
      llm: new ChatOpenAI({ temperature: 0 }),
      prompt: promptTemplate,
      outputKey: "synopsis",
    }),
    new LLMChain({
      llm: new OpenAI({ temperature: 0 }),
      prompt: reviewPromptTemplate,
      outputKey: "review",
    }),
  ],
  inputVariables: ["era", "title"],
  outputVariables: ["synopsis", "review"],
  verbose: true,
});

const chainExecutionResult = await overallChain.call({
  title: "Tragedy at sunset on the beach",
  era: "Victorian England",
});
console.log(chainExecutionResult);

Deprecated

Switch to expression language. Will be removed in 0.2.0

Hierarchy (view full)

Implements

Constructors

constructor

Properties

chains inputVariables outputVariables memory? returnAll?

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.

inputVariables

inputVariables: string[]

Defines which variables should be passed as initial input to the first chain.

outputVariables

outputVariables: string[]

Which variables should be returned as a result of executing the chain. If not specified, output of the last of the chains is used.

Optional memory

memory?: BaseMemory

Optional returnAll

returnAll?: boolean

Whether or not to return all intermediate outputs and variables (excluding initial input variables).

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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