Disclaimer: a dumb little start to leveling up my AI fluency. Nothing fancy, no grand architecture, no hot takes — just a journal of me trying to actually understand things instead of pretending to.
Quick filter: if you're on React 19, have actually enabled the compiler (it's an opt-in plugin, not something the version hands you for free), and you write pure components — close the tab, you already know the ending. If you're on React 19 and assumed that meant the compiler was on: stay. That assumption is a trap, and I fell in it.
Why chat is Project 1
Streaming tokens into a growing list that re-renders on every one is the substrate under every AI feature I'm about to build — RAG answers stream, agents stream, all of it. If I can't make token-by-token rendering behave, nothing downstream will.
So the rule I gave myself: build it by hand before reaching for the library. No useChat until I've felt the problem it solves. I did it in Next.js — partly because that's where I'm headed, partly as an excuse to learn it — but none of this is Next-specific; any framework does the same thing. And I mocked the stream instead of calling a real model, because the subject is how the UI handles a stream, not the model. A real LLM would just be a slower way to make the same tokens.
