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 verbose callbacks? memory? metadata? returnAll? tags?

Accessors

inputKeys outputKeys

Methods

apply batch bind call invoke map pipe prepOutputs run serialize stream streamLog toJSON toJSONNotImplemented transform withConfig withFallbacks withRetry deserialize isRunnable

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.

verbose

verbose: boolean

Whether to print out response text.

Optional callbacks

callbacks?: Callbacks

Optional memory

memory?: BaseMemory

Optional metadata

metadata?: Record<string, unknown>

Optional returnAll

returnAll?: boolean

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

Optional tags

tags?: string[]

Accessors

inputKeys

  • get inputKeys(): string[]

  • Returns string[]

outputKeys

  • get outputKeys(): string[]

  • Returns string[]

Methods

apply

batch

bind

call

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

    Wraps _call and handles memory.

    Parameters

    Returns Promise<ChainValues>

invoke

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

    Parameters

    Returns Promise<ChainValues>

    Promise that resolves with the output of the chain run.

map

pipe

  • Create a new runnable sequence that runs each individual runnable in series, piping the output of one runnable into another runnable or runnable-like.

    Type Parameters

    • NewRunOutput

    Parameters

    • coerceable: RunnableLike<ChainValues, NewRunOutput>

      A runnable, function, or object whose values are functions or runnables.

    Returns RunnableSequence<ChainValues, Exclude<NewRunOutput, Error>>

    A new runnable sequence.

prepOutputs

  • Parameters

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

    Returns Promise<Record<string, unknown>>

run

  • Parameters

    Returns Promise<string>

serialize

stream

  • Stream output in chunks.

    Parameters

    Returns Promise<IterableReadableStream<ChainValues>>

    A readable stream that is also an iterable.

streamLog

  • Stream all output from a runnable, as reported to the callback system. This includes all inner runs of LLMs, Retrievers, Tools, etc. Output is streamed as Log objects, which include a list of jsonpatch ops that describe how the state of the run has changed in each step, and the final state of the run. The jsonpatch ops can be applied in order to construct state.

    Parameters

    Returns AsyncGenerator<RunLogPatch, any, unknown>

toJSON

toJSONNotImplemented

transform

  • Default implementation of transform, which buffers input and then calls stream. Subclasses should override this method if they can start producing output while input is still being generated.

    Parameters

    Returns AsyncGenerator<ChainValues, any, unknown>

withConfig

withFallbacks

withRetry

Static deserialize

Static isRunnable

Settings

Member Visibility

Theme

On This Page

Generated using TypeDoc