🧠LangChain-Tutorial (JavaScript)

Hi! I'm Yatharth, and this is my personal LangChain learning repo.
I'm exploring how to use LangChain with JavaScript to build AI-powered applications using large language models (LLMs) like OpenAI, Groq, and others.

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💡What is LangChain?

LangChain is a framework that helps developers build apps powered by LLMs.
It connects language models with external tools like APIs, databases, files, and more.

With LangChain, you can create things like:

• Chatbots 💬
• AI agents that call APIs 🔗
• Document Q&A tools 📄
• Search + reasoning apps 🔍🧠

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🛠️What I'm Doing Here

I'm using Node.js and JavaScript with LangChain to:

• Set up my first chatbot using the ChatOpenAI/ChatGroq class.
• Learn how to connect to Groq and OpenAI APIs.
• Test LLM responses using .invoke() calls.
• Handle .env files securely for API keys.
• Understand error handling for quota limits and model issues.

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📂Files in This Project

• llm.js – Test file to send prompts to an LLM.
• prompt-template.js: Contains logic for creating and managing prompt templates, which are used to structure input for language models.
• output-parsers.js: Provides utilities for parsing and processing the output generated by LLM.
• retrieval-chain.js:
• .env – Stores API keys (not uploaded).
• package.json – Dependencies.
• README.md – You're reading it 😊

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✅Example Output

> node llm.js
llm.js loaded 2025-06-01T11:27:39.413Z
Response from LLM: ************************

🌐Models I'm Trying

OpenAI: gpt-3.5-turbo (but needs paid quota🥹)
Groq: Fast models like llama3-8b (free & good alternative)

🚧Still Learning...

I'm figuring out:

• How to chain prompts together.
• How to use memory and tools with agents.
• How to switch models easily (OpenAI, Groq, Cohere, etc).

🤝Let's Connect

If you're also learning LangChain or building AI stuff, feel free to connect! Made with ❤️ by Yatharth