Langchain don't support basic things, like splitting a list result in single items and processing those one by one, accumulating the results further down the road.

By the time you have built custom chains, custom prompts, and custom agents to support all that, you basically are using their interface and not their code. At that point, eh, it's pointless. It's great for demos, I give you that, but every time I tried to coherce it into a product, it fell short.

React works. NextJS works. OpenAI's ChatCompletion API with `functions` works. Go on langchain's discord and ask their documentation bot anything.

The question is: Who needs to abtract over 10 lines of code?