# index

> **Module** in `langchain`

📖 [View in docs](https://reference.langchain.com/javascript/langchain/index)

## Signature

```javascript
index
```

## Methods

- [`anthropicPromptCachingMiddleware()`](https://reference.langchain.com/javascript/langchain/index/anthropicPromptCachingMiddleware)
- [`applyStrategy()`](https://reference.langchain.com/javascript/langchain/index/applyStrategy)
- [`context()`](https://reference.langchain.com/javascript/langchain/index/context)
- [`contextEditingMiddleware()`](https://reference.langchain.com/javascript/langchain/index/contextEditingMiddleware)
- [`countTokensApproximately()`](https://reference.langchain.com/javascript/langchain/index/countTokensApproximately)
- [`createAgent()`](https://reference.langchain.com/javascript/langchain/index/createAgent)
- [`createMiddleware()`](https://reference.langchain.com/javascript/langchain/index/createMiddleware)
- [`detectCreditCard()`](https://reference.langchain.com/javascript/langchain/index/detectCreditCard)
- [`detectEmail()`](https://reference.langchain.com/javascript/langchain/index/detectEmail)
- [`detectIP()`](https://reference.langchain.com/javascript/langchain/index/detectIP)
- [`detectMacAddress()`](https://reference.langchain.com/javascript/langchain/index/detectMacAddress)
- [`detectUrl()`](https://reference.langchain.com/javascript/langchain/index/detectUrl)
- [`dynamicSystemPromptMiddleware()`](https://reference.langchain.com/javascript/langchain/index/dynamicSystemPromptMiddleware)
- [`fakeModel()`](https://reference.langchain.com/javascript/langchain/index/fakeModel)
- [`filterMessages()`](https://reference.langchain.com/javascript/langchain/index/filterMessages)
- [`humanInTheLoopMiddleware()`](https://reference.langchain.com/javascript/langchain/index/humanInTheLoopMiddleware)
- [`llmToolSelectorMiddleware()`](https://reference.langchain.com/javascript/langchain/index/llmToolSelectorMiddleware)
- [`modelCallLimitMiddleware()`](https://reference.langchain.com/javascript/langchain/index/modelCallLimitMiddleware)
- [`modelFallbackMiddleware()`](https://reference.langchain.com/javascript/langchain/index/modelFallbackMiddleware)
- [`modelRetryMiddleware()`](https://reference.langchain.com/javascript/langchain/index/modelRetryMiddleware)
- [`openAIModerationMiddleware()`](https://reference.langchain.com/javascript/langchain/index/openAIModerationMiddleware)
- [`piiMiddleware()`](https://reference.langchain.com/javascript/langchain/index/piiMiddleware)
- [`piiRedactionMiddleware()`](https://reference.langchain.com/javascript/langchain/index/piiRedactionMiddleware)
- [`providerStrategy()`](https://reference.langchain.com/javascript/langchain/index/providerStrategy)
- [`resolveRedactionRule()`](https://reference.langchain.com/javascript/langchain/index/resolveRedactionRule)
- [`summarizationMiddleware()`](https://reference.langchain.com/javascript/langchain/index/summarizationMiddleware)
- [`todoListMiddleware()`](https://reference.langchain.com/javascript/langchain/index/todoListMiddleware)
- [`tool()`](https://reference.langchain.com/javascript/langchain/index/tool)
- [`toolCallLimitMiddleware()`](https://reference.langchain.com/javascript/langchain/index/toolCallLimitMiddleware)
- [`toolEmulatorMiddleware()`](https://reference.langchain.com/javascript/langchain/index/toolEmulatorMiddleware)
- [`toolRetryMiddleware()`](https://reference.langchain.com/javascript/langchain/index/toolRetryMiddleware)
- [`toolStrategy()`](https://reference.langchain.com/javascript/langchain/index/toolStrategy)
- [`trimMessages()`](https://reference.langchain.com/javascript/langchain/index/trimMessages)
- [`initChatModel()`](https://reference.langchain.com/javascript/langchain/index/initChatModel)

---

[View source on GitHub](https://github.com/langchain-ai/langchainjs/blob/b0175a5d3b68e8fba44a85bc23879bd06def2f52/libs/langchain/src/index.ts#L1)