LangChain 프롬프트 템플릿 패턴 정리 (TypeScript) — Few-shot, Partial, Pipeline

import { PromptTemplate } from "@langchain/core/prompts";

const examplePrompt = PromptTemplate.fromTemplate(
  "Question: {question}\n{answer}"
);

const examples = [
  {
    question: "Who lived longer, Muhammad Ali or Alan Turing?",
    answer: `
Are follow up questions needed here: Yes.
Follow up: How old was Muhammad Ali when he died?
Intermediate answer: Muhammad Ali was 74 years old when he died.
Follow up: How old was Alan Turing when he died?
Intermediate answer: Alan Turing was 41 years old when he died.
So the final answer is: Muhammad Ali
    `,
  },
  {
    question: "When was the founder of craigslist born?",
    answer: `
Are follow up questions needed here: Yes.
Follow up: Who was the founder of craigslist?
Intermediate answer: Craigslist was founded by Craig Newmark.
Follow up: When was Craig Newmark born?
Intermediate answer: Craig Newmark was born on December 6, 1952.
So the final answer is: December 6, 1952
    `,
  },
];

import { FewShotPromptTemplate } from "@langchain/core/prompts";

const prompt = new FewShotPromptTemplate({
  examples,
  examplePrompt,
  suffix: "Question: {input}",
  inputVariables: ["input"],
});

const formatted = await prompt.format({
  input: "Who was the father of Mary Ball Washington?",
});

console.log(formatted.toString());

import { PromptTemplate } from "langchain/prompts";

const prompt = new PromptTemplate({
  template: "{foo}{bar}",
  inputVariables: ["foo", "bar"],
});

// foo를 먼저 바인딩
const partialPrompt = await prompt.partial({
  foo: "foo",
});

// 나중에 bar만 전달
const formattedPrompt = await partialPrompt.format({
  bar: "baz",
});

console.log(formattedPrompt);
// foobaz

// 앱 초기화 시 시스템 언어/지역 설정 바인딩
const basePrompt = new PromptTemplate({
  template: "You are a helpful assistant. Language: {language}. User query: {query}",
  inputVariables: ["language", "query"],
});

const koreanPrompt = await basePrompt.partial({ language: "Korean" });

// 이후 요청마다 query만 전달
const result = await koreanPrompt.format({ query: "오늘 날씨 어때?" });

import {
  PromptTemplate,
  PipelinePromptTemplate,
} from "@langchain/core/prompts";

// 최종 템플릿 — 서브 프롬프트를 변수처럼 참조
const fullPrompt = PromptTemplate.fromTemplate(`{introduction}

{example}

{start}`);

// 서브 프롬프트 1: 페르소나 설정
const introductionPrompt = PromptTemplate.fromTemplate(
  `You are impersonating {person}.`
);

// 서브 프롬프트 2: 예시 대화
const examplePrompt = PromptTemplate.fromTemplate(
  `Here's an example of an interaction:
Q: {example_q}
A: {example_a}`
);

// 서브 프롬프트 3: 실제 질문
const startPrompt = PromptTemplate.fromTemplate(
  `Now, do this for real!
Q: {input}
A:`
);

const composedPrompt = new PipelinePromptTemplate({
  pipelinePrompts: [
    { name: "introduction", prompt: introductionPrompt },
    { name: "example", prompt: examplePrompt },
    { name: "start", prompt: startPrompt },
  ],
  finalPrompt: fullPrompt,
});

const formattedPrompt = await composedPrompt.format({
  person: "Elon Musk",
  example_q: `What's your favorite car?`,
  example_a: "Tesla",
  input: `What's your favorite social media site?`,
});

console.log(formattedPrompt);