# Topic

> **Interface** in `@langchain/langgraph`

📖 [View in docs](https://reference.langchain.com/javascript/langchain-langgraph/channels/Topic)

A configurable PubSub Topic.

## Signature

```javascript
interface Topic
```

## Properties

- `accumulate`
- `lc_graph_name`
- `seen`
- `unique`
- `UpdateType`
- `values`
- `ValueType`

## Methods

- [`checkpoint()`](https://reference.langchain.com/javascript/langchain-langgraph/channels/Topic/checkpoint)
- [`consume()`](https://reference.langchain.com/javascript/langchain-langgraph/channels/Topic/consume)
- [`equals()`](https://reference.langchain.com/javascript/langchain-langgraph/channels/Topic/equals)
- [`finish()`](https://reference.langchain.com/javascript/langchain-langgraph/channels/Topic/finish)
- [`fromCheckpoint()`](https://reference.langchain.com/javascript/langchain-langgraph/channels/Topic/fromCheckpoint)
- [`get()`](https://reference.langchain.com/javascript/langchain-langgraph/channels/Topic/get)
- [`isAvailable()`](https://reference.langchain.com/javascript/langchain-langgraph/channels/Topic/isAvailable)
- [`update()`](https://reference.langchain.com/javascript/langchain-langgraph/channels/Topic/update)

---

[View source on GitHub](https://github.com/langchain-ai/langgraphjs/blob/dc37d3cd62bf88272cdc874e37354ae83ac01660/libs/langgraph-core/src/channels/topic.ts#L7)