[Runnable | LangChain.js](https://api.js.langchain.com/classes/langchain_core.runnables.Runnable.html/): LLM should read this page when: 1) Learning about the core concepts and components of LangChain.js 2) Understanding how to create and customize Runnables 3) Integrating custom event streaming into Runnables The page describes the Runnable class in LangChain.js, which is an abstract base class for creating units of work that can be invoked, batched, streamed, and transformed. It provides documentation on the Runnable class's properties, methods, and inheritance hierarchy, as well as examples of creating custom Runnables and integrating event streaming.

