[Mistake]: The demo of useOptimistic may occur an incorrect rendering

[felismargarita]

Summary

useOptimistic demo merges state via [...state, { text: newMessage, sending:true }], which may render a same message twice in the page at the same time(although it will render correct page immediately after the incorrect one)

Page

https://react.dev/reference/react/useOptimistic

Details

merge message logic in this demo has to handle the situation:
state(array of the messages) already includes the sending message when the setMessages is called to make the page re-rendering.

[karthik-awebon]

Hello @felismargarita the existing code effectively demonstrates the use of the UseOptimistic Hook with a simple example. Adding unnecessary complexity to handle duplicate messages detracts from the core purpose of the demo.

Additionally, your PR does not function as intended. The use of time as a unique identifier for messages is flawed, as identical messages can still appear multiple times if their timestamps differ, as evidenced in the screenshot.
image