Class TextPromptClient

constructor

• new TextPromptClient(prompt: Text, isFallback?: boolean): TextPromptClient

  Creates a new TextPromptClient instance.

  Parameters

  • prompt: Text

    The text prompt data
  • isFallback: boolean = false

    Whether this is fallback content

  Returns TextPromptClient

Readonlyprompt

ReadonlypromptResponse

compile

• compile(
      variables?: Record<string, string>,
      _placeholders?: Record<string, any>,
  ): string

  Compiles the text prompt by substituting variables.

  Uses Mustache templating to replace {{variable}} placeholders with provided values.

  Parameters

  • Optionalvariables: Record<string, string>

    Key-value pairs for variable substitution
  • Optional_placeholders: Record<string, any>

    Ignored for text prompts

  Returns string

  The compiled text with variables substituted

  Example

  const prompt = await langfuse.prompt.get("greeting", { type: "text" });
  const compiled = prompt.compile({ name: "Alice" });
  // If prompt is "Hello {{name}}!", result is "Hello Alice!"
  Copy

getLangchainPrompt

• getLangchainPrompt(_options?: { placeholders?: Record<string, any> }): string

  Converts the prompt to LangChain PromptTemplate format.

  Transforms Mustache-style {{variable}} syntax to LangChain's {variable} format.

  Parameters

  • Optional_options: { placeholders?: Record<string, any> }

    Ignored for text prompts

  Returns string

  The prompt string compatible with LangChain PromptTemplate

  Example

  const prompt = await langfuse.prompt.get("greeting", { type: "text" });
  const langchainFormat = prompt.getLangchainPrompt();
  // Transforms "Hello {{name}}!" to "Hello {name}!"
  Copy

toJSON

• toJSON(): string

  Serializes the prompt client to JSON.

  Returns string

  JSON string representation of the prompt