fix(raf-state): accumulate updates passed between repaints

[einouqo]

Currently, updates scheduled via useRafState are deferred to the next frame, canceling previously scheduled update. If multiple function updates (e.g. setState(prev => prev + 1)) occur between repaint cycles, only the last update is executed, and previous intermediate state transitions are lost.

In the demo, the double callback should increment the counter twice by calling setCount((v) => v + 1) two times. However, only the last call is actually executed on the repaint, so instead of resulting in +2, it results in +1.

What was changed

• fixed useRafState to accumulate state changes and only set the final state value on repaint (next frame)
• refactored update state tests into a parameterized suite (value, function, and mixed updates)

[Copilot]

Pull request overview

This PR fixes a bug in useRafState where multiple function updates (e.g., setState(prev => prev + 1)) scheduled between repaint cycles would not accumulate properly, with only the last update being executed. The fix introduces state accumulation logic using a ref to track intermediate state changes.

Changes:

• Modified useRafState to accumulate state updates in a ref between repaints, ensuring all functional updates are applied correctly
• Refactored tests into parameterized test cases covering value updates, function updates, and mixed updates

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/react-use/src/use-raf-state/index.ts	Added ref-based accumulation logic with new imports (useCallback, useRef, isFunction) and custom setter callback to properly chain functional updates
packages/react-use/src/use-raf-state/index.test.ts	Converted multiple update tests into parameterized test suite with three scenarios (value, function, and mixed updates) to verify accumulation behavior

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[vikiboss]

Thanks!