fix: typing in ChatInput no longer causes unnecessary rerenders #136
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This update refactors the Chat component by streamlining the useChat hook and removing unnecessary state management for input handling. The ChatInput component has been enhanced to handle message submission more effectively, including resetting the textarea after submission. Additionally, a new test suite for the ChatInput component has been added, covering rendering, message submission, and input behavior, ensuring better reliability and maintainability of the chat functionality.
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This PR fixes a major performance issue in the chat UI. Previously, typing in the chat prompt input triggered a rerender of the entire chat message list—, including all message rows on every keystroke.
With a test harness of 1,000 messages and CPU throttled to 4x CPU slowdown, this caused severe UI lag (typing a short phrase could take over 10 seconds to appear).
What Changed:
Chatcomponent and the message list only rerender on new messages, not on input changes.Impact (with 1,000 messages, 4x CPU slowdown):
"this is me typing"took over 10 seconds to appearResult:
Closes #128
Note: As a good follow up, implementing #118 will also improve performance.
Screenshots and Videos
Here is the fix in action with 1000 fake bot messages injected and CPU throttling set to 4x slowdown.
Before
CleanShot.2025-07-13.at.09.02.11.mp4
After
CleanShot.2025-07-13.at.09.03.13.mp4