Class: ChatPromptTemplate

prompts.ChatPromptTemplate

Base class for prompt templates. Exposes a format method that returns a string prompt given a set of input values.

Hierarchy

• BaseChatPromptTemplate

  ↳ ChatPromptTemplate

Implements

• ChatPromptTemplateInput

Constructors

constructor

• new ChatPromptTemplate(input)

Parameters

Name	Type
input	ChatPromptTemplateInput

Overrides

BaseChatPromptTemplate.constructor

Defined in

langchain/src/prompts/chat.ts:186

Properties

inputVariables

• inputVariables: string[]

A list of variable names the prompt template expects

Implementation of

ChatPromptTemplateInput.inputVariables

Inherited from

BaseChatPromptTemplate.inputVariables

Defined in

langchain/src/prompts/base.ts:51

---

outputParser

• Optional outputParser: BaseOutputParser

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

Implementation of

ChatPromptTemplateInput.outputParser

Inherited from

BaseChatPromptTemplate.outputParser

Defined in

langchain/src/prompts/base.ts:53

---

partialVariables

• Optional partialVariables: InputValues

Partial variables

Implementation of

ChatPromptTemplateInput.partialVariables

Inherited from

BaseChatPromptTemplate.partialVariables

Defined in

langchain/src/prompts/base.ts:55

---

promptMessages

• promptMessages: BaseMessagePromptTemplate[]

Implementation of

ChatPromptTemplateInput.promptMessages

Defined in

langchain/src/prompts/chat.ts:182

---

validateTemplate

• validateTemplate: boolean = true

Implementation of

ChatPromptTemplateInput.validateTemplate

Defined in

langchain/src/prompts/chat.ts:184

Methods

_getPromptType

▸ _getPromptType(): "chat"

Return the string type key uniquely identifying this class of prompt template.

Returns

"chat"

Overrides

BaseChatPromptTemplate._getPromptType

Defined in

langchain/src/prompts/chat.ts:229

---

format

▸ format(values): Promise<string>

Format the prompt given the input values.

Example

prompt.format({ foo: "bar" });

Parameters

Name	Type	Description
values	InputValues	A dictionary of arguments to be passed to the prompt template.

Returns

Promise<string>

A formatted prompt string.

Inherited from

BaseChatPromptTemplate.format

Defined in

langchain/src/prompts/chat.ts:95

---

formatMessages

▸ formatMessages(values): Promise<BaseChatMessage[]>

Parameters

Name	Type
values	InputValues

Returns

Promise<BaseChatMessage[]>

Overrides

BaseChatPromptTemplate.formatMessages

Defined in

langchain/src/prompts/chat.ts:233

---

formatPromptValue

▸ formatPromptValue(values): Promise<BasePromptValue>

Format the prompt given the input values and return a formatted prompt value.

Parameters

Name	Type
values	InputValues

Returns

Promise<BasePromptValue>

A formatted PromptValue.

Inherited from

BaseChatPromptTemplate.formatPromptValue

Defined in

langchain/src/prompts/chat.ts:99

---

mergePartialAndUserVariables

▸ mergePartialAndUserVariables(userVariables): Promise<InputValues>

Parameters

Name	Type
userVariables	InputValues

Returns

Promise<InputValues>

Inherited from

BaseChatPromptTemplate.mergePartialAndUserVariables

Defined in

langchain/src/prompts/base.ts:69

---

partial

▸ partial(values): Promise<BasePromptTemplate>

Parameters

Name	Type
values	PartialValues

Returns

Promise<BasePromptTemplate>

Overrides

BaseChatPromptTemplate.partial

Defined in

langchain/src/prompts/chat.ts:265

---

serialize

▸ serialize(): SerializedChatPromptTemplate

Return a json-like object representing this prompt template.

Returns

SerializedChatPromptTemplate

Overrides

BaseChatPromptTemplate.serialize

Defined in

langchain/src/prompts/chat.ts:253

---

deserialize

▸ Static deserialize(data): Promise<BasePromptTemplate>

Load a prompt template from a json-like object describing it.

Remarks

Deserializing needs to be async because templates (e.g. FewShotPromptTemplate) can reference remote resources that we read asynchronously with a web request.

Parameters

Name	Type
data	SerializedBasePromptTemplate

Returns

Promise<BasePromptTemplate>

Inherited from

BaseChatPromptTemplate.deserialize

Defined in

langchain/src/prompts/base.ts:125

---

fromPromptMessages

▸ Static fromPromptMessages(promptMessages): ChatPromptTemplate

Parameters

Name	Type
promptMessages	BaseMessagePromptTemplate[]

Returns

ChatPromptTemplate

Defined in

langchain/src/prompts/chat.ts:279