fix(assignee-selector): split autofocus inp cost over multiple frames #64165
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snigdhas
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…#64165) This PR reduces the INP impact of the autofocus react attribute by deferring the focus event until next frame. Calling [.focus](https://gist.github.com/paulirish/5d52fb081b3570c81e3a) causes layout thrashing which causes UI jank. We are currently able to observe this using browser profiling where a lot of the call stacks point towards a .focus perf culprit.  Having looked at prod profiles and react source, the function responsible for calling .focus is [commitMount](https://github.com/facebook/react/blob/2477384650bd184d3ac4a881130118f2636f8551/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js#L676), called during a finalizeInitialChildren. I did not verify when exactly this is called, but from the profiling data, this always appears to always be the last function in the call stacks when committing changes to the DOM. The PR mitigates the sync nature of the .focus call by removing the autofocus attribute and scheduling the autofocus to be performed in the next browser event loop tick, yielding to the engine and splitting the cost over two multiple browser frames.
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Same optimization as #64165 - defer focus event to next frame.
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This PR reduces the INP impact of the autofocus react attribute by deferring the focus event until next frame.
Calling .focus causes layout thrashing which causes UI jank. We are currently able to observe this using browser profiling where a lot of the call stacks point towards a .focus perf culprit.
Having looked at prod profiles and react source, the function responsible for calling .focus is commitMount, called during a finalizeInitialChildren. I did not verify when exactly this is called, but from the profiling data, this always appears to always be the last function in the call stacks when committing changes to the DOM.
The PR mitigates the sync nature of the .focus call by removing the autofocus attribute and scheduling the autofocus to be performed in the next browser event loop tick, yielding to the engine and splitting the cost over two multiple browser frames.