Class ChatPromptTemplate<RunInput, PartialVariableName>

Class that represents a chat prompt. It extends the BaseChatPromptTemplate and uses an array of BaseMessagePromptTemplate instances to format a series of messages for a conversation.

Example

const message = SystemMessagePromptTemplate.fromTemplate("{text}");
const chatPrompt = ChatPromptTemplate.fromMessages([
["ai", "You are a helpful assistant."],
message,
]);
const formattedChatPrompt = await chatPrompt.invoke({
text: "Hello world!",
});

Type Parameters

  • RunInput extends InputValues = any

  • PartialVariableName extends string = any

Hierarchy

Implements

Constructors

Properties

PromptValueReturnType: ChatPromptValueInterface
inputVariables: Extract<keyof RunInput, string>[]

A list of variable names the prompt template expects

partialVariables: PartialValues<PartialVariableName>

Partial variables

promptMessages: (BaseMessage | BaseMessagePromptTemplate<any, BaseMessage[]>)[]

The prompt messages

validateTemplate: boolean = true

Whether to try validating the template on initialization

Default Value

true

name?: string
outputParser?: BaseOutputParser<unknown>

How to parse the output of calling an LLM on this formatted prompt

Methods

  • 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>

  • Bind lifecycle listeners to a Runnable, returning a new Runnable. The Run object contains information about the run, including its id, type, input, output, error, startTime, endTime, and any tags or metadata added to the run.

    Parameters

    • params: {
          onEnd?: ((run, config?) => void | Promise<void>);
          onError?: ((run, config?) => void | Promise<void>);
          onStart?: ((run, config?) => void | Promise<void>);
      }

      The object containing the callback functions.

      • Optional onEnd?: ((run, config?) => void | Promise<void>)
          • (run, config?): void | Promise<void>
          • Called after the runnable finishes running, with the Run object.

            Parameters

            Returns void | Promise<void>

      • Optional onError?: ((run, config?) => void | Promise<void>)
          • (run, config?): void | Promise<void>
          • Called if the runnable throws an error, with the Run object.

            Parameters

            Returns void | Promise<void>

      • Optional onStart?: ((run, config?) => void | Promise<void>)
          • (run, config?): void | Promise<void>
          • Called before the runnable starts running, with the Run object.

            Parameters

            Returns void | Promise<void>

    Returns Runnable<RunInput, ChatPromptValueInterface, RunnableConfig>

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