Add WhatsApp Chat Document Loader (Python parity)

[kukjun]

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Feature request

Add a WhatsApp Chat Loader to LangChain.js, matching the functionality available in LangChain Python.

Motivation

WhatsApp is one of the most widely used messaging platforms globally (2B+ users), and chat export is a common use case for conversational AI and RAG applications. The Python implementation exists but the JS/TS version doesn't, creating a gap for developers who need this functionality.

Why this matters:

1. Feature parity with Python implementation - ensures consistency across the LangChain ecosystem
2. High demand - WhatsApp chat analysis is a frequent use case for conversation history, customer support analysis, and knowledge extraction
3. Simple implementation - Text file parsing only, no external API dependencies or authentication required
4. Low maintenance burden - Standard .txt export format with well-defined structure

Reference:

• Python implementation: https://python.langchain.com/api_reference/community/chat_loaders/langchain_community.chat_loaders.whatsapp.WhatsAppChatLoader.html

Proposal (If applicable)

Important discovery: This is actually a Chat Loader, not a Document Loader. It returns ChatSession objects with HumanMessage instances, preserving the conversational structure.

Implementation approach:

• Type: Chat Loader (Document Loader)
• Location: libs/langchain-community/src/chat_loaders/whatsapp.ts
• Entrypoint: @langchain/community/chat_loaders/whatsapp
• Input: Exported WhatsApp chat files (.txt format, without media)
• Output: ChatSession with HumanMessage objects containing sender and timestamp metadata
• Features:
  • Multi-line message support
  • System message filtering (deleted messages, media omitted, etc.)
  • Timestamp and sender extraction
  • Support for both 12-hour (AM/PM) and 24-hour formats
• Dependencies: None (pure text parsing with regex)
• Tests: Integration tests with sample chat exports

Example usage:

import { WhatsAppChatLoader } from "@langchain/community/chat_loaders/whatsapp";

const loader = new WhatsAppChatLoader("path/to/chat.txt");
const chatSessions = await loader.load();
// Returns ChatSession with HumanMessage objects

Question: Given the simplicity of this loader and low maintenance requirements, would it be acceptable to contribute this directly to @langchain/community, or should this be published as a standalone NPM package per the current integration guidelines? I'm ready to implement this with full tests and documentation if this is welcome in the main repository.