fix: improve ZWS handling performance on iOS

[IvanIhnatsiuk]

Summary

This pull request introduces several improvements to the handling of zero-width spaces (ZWS) in enriched text input, focusing on better style detection, more robust editing, and improved method signatures. The main changes include passing ZWS styles explicitly to relevant methods, ensuring batch editing of text storage for performance, and refining how placeholder logic is applied for block elements.

Zero-width space handling and style detection:

• Refactored ZeroWidthSpaceUtils methods (removeSpacesIfNeededinInput and addSpacesIfNeededinInput) to accept an explicit zwsStyles parameter, ensuring consistent style checks and reducing redundant style computation.
• Added a new overload findAnyZWSStylesInInput:range:zwsStyles: to check for ZWS styles within a range using a provided styles array, improving accuracy and efficiency when determining where ZWS handling is needed.

Batch editing and performance:

• Wrapped text storage modifications in beginEditing/endEditing calls during ZWS removal and insertion, reducing the number of layout and notification events for better performance and stability.

Code quality and correctness:

• Updated pointer checks from nullptr to nil for Objective-C compatibility in handleZeroWidthSpacesInInput.

HTML parsing logic:

• Adjusted placeholder logic in traverseNode: to only insert placeholders for list items and check list tags, not for all paragraph tags, making block placeholder insertion more precise.

Test Plan

Provide clear steps so another contributor can reproduce the behavior or verify the feature works.
For example:

• Steps to reproduce the bug (if this is a bug fix)
• Steps to verify the new feature
• Expected vs actual results
• Any special conditions or edge cases to test

Screenshots / Videos

Include any visual proof that helps reviewers understand the change — UI updates, bug reproduction or the result of the fix.

Compatibility

OS	Implemented
iOS	✅
Android	❌

[Copilot]

Pull request overview

This PR refactors iOS zero-width space (ZWS) handling in EnrichedTextInputView to reduce redundant style detection and improve text storage edit performance, and it tightens HTML parsing placeholder insertion rules for block elements.

Changes:

• Passes precomputed zwsStyles through ZWS add/remove flows and adds an overload for style checks to avoid recomputing styles repeatedly.
• Wraps ZWS insertion/removal mutations in NSTextStorage beginEditing/endEditing to reduce intermediate layout/notification churn.
• Refines HTML empty-block placeholder insertion to focus on list-related tags.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
ios/utils/Text/ZeroWidthSpaceUtils.mm	Refactors ZWS style detection to accept explicit styles and batches text storage edits for performance.
ios/parser/EnrichedHTMLToAttributedStringParser.mm	Narrows when ZWS placeholders are inserted for empty block elements during HTML traversal.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.