add initial previous value param to usePrevious hook #316
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary
Add optional initial value parameter to usePrevious hook and fix typescript
Reason
1. Performance Issue
The current implementation uses two useState hooks and updates state during render, which can cause unnecessary re-renders and violate React's rendering rules:
2. Initial Value
The hook always returns null as the initial previous value, which causes issues in scenarios where a different initial value is needed:
3. Wrong Type
Current type definition doesn't accurately represent the hook's behavior: