Class RetrievalQAChain

Class representing a chain for performing question-answering tasks with a retrieval component.

Example

// Initialize the OpenAI model and the remote retriever with the specified configuration
const model = new ChatOpenAI({});
const retriever = new RemoteLangChainRetriever({
  url: "http://example.com/api",
  auth: { bearer: "foo" },
  inputKey: "message",
  responseKey: "response",
});

// Create a RetrievalQAChain using the model and retriever
const chain = RetrievalQAChain.fromLLM(model, retriever);

// Execute the chain with a query and log the result
const res = await chain.call({
  query: "What did the president say about Justice Breyer?",
});
console.log({ res });

Hierarchy

Implements

Constructors

constructor

Properties

combineDocumentsChain inputKey retriever returnSourceDocuments memory?

Accessors

inputKeys outputKeys

Methods

apply call invoke prepOutputs run serialize deserialize fromLLM

Constructors

constructor

Properties

combineDocumentsChain

combineDocumentsChain: BaseChain<ChainValues, ChainValues>

inputKey

inputKey: string = "query"

retriever

retriever: BaseRetriever

returnSourceDocuments

returnSourceDocuments: boolean = false

Optional memory

memory?: BaseMemory

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

Static fromLLM

  • Creates a new instance of RetrievalQAChain using a BaseLanguageModel and a BaseRetriever.

    Parameters

    • llm: BaseLanguageModel<any, BaseLanguageModelCallOptions>

      The BaseLanguageModel used to generate a new question.

    • retriever: BaseRetriever

      The BaseRetriever used to retrieve relevant documents.

    • Optional options: Partial<Omit<RetrievalQAChainInput, "combineDocumentsChain" | "retriever" | "index">> & StuffQAChainParams

      Optional parameters for the RetrievalQAChain.

    Returns RetrievalQAChain

    A new instance of RetrievalQAChain.

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