Some demo code to showcase converting an app to using React hooks.

First get this API up and running: https://github.com/spiderbites/hookchat-api

Then...

yarn install
yarn start

In ./src/index.js, swap the import statement to move between the classic version and the hooks version.

Docs

tl;dr Wrap a functional component with React.memo to only re-render when props change. If the props don't change, "React will skip rendering the component, and reuse the last rendered result."

The images below were produced using the React Dev Tools profiler.

Note that in reality you'd want to use a windowing solution to render long lists of messages, this is simply for demonstration.

The grey bars indicate message components were not re-rendered. Also note the total time for the commit phases.

Each bar in the chart represents a component, ordered by how long they took to render.