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);

Hierarchy

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

  • get inputKeys(): string[]

  • Returns string[]

outputKeys

  • get outputKeys(): string[]

  • Returns string[]

Methods

apply

  • Call the chain on all inputs in the list

    Parameters

    • inputs: ChainValues[]
    • Optional config: (BaseCallbackConfig | Callbacks)[]

    Returns Promise<ChainValues[]>

call

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

    Wraps _call and handles memory.

    Parameters

    • values: ChainValues & {
          signal?: AbortSignal;
          timeout?: number;
      }
    • Optional config: BaseCallbackConfig | Callbacks
    • Optional tags: string[]

      Deprecated

    Returns Promise<ChainValues>

invoke

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

    Parameters

    • input: ChainValues

      Input values for the chain run.

    • Optional config: BaseCallbackConfig

      Optional configuration for the Runnable.

    Returns Promise<ChainValues>

    Promise that resolves with the output of the chain run.

prepOutputs

  • Parameters

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

    Returns Promise<Record<string, unknown>>

run

  • Parameters

    • input: any
    • Optional config: BaseCallbackConfig | Callbacks

    Returns Promise<string>

serialize

Static deserialize

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