# Changes

## [Unreleased]

### Added

**RepeatingGroup Duplicate Detection**
- Implemented duplicate item validation across all backends (CLI, TUI, Web)
- Added `unique = true` attribute support to prevent duplicate items
- Added item counter display updates in Web backend
- New `is_duplicate()` function in CLI and TUI backends

**Web Backend Improvements**
- Refactored JavaScript: Replaced global constants with closure-based state management
- Added `render_global_repeating_group_script()` for generic repeating group handling
- Configuration stored in `data-*` attributes: `data-min-items`, `data-max-items`, `data-has-unique`, `data-unique-key`, `data-field-names`
- Live item counter updates after add/delete operations
- Single document-level event delegation for all repeating group interactions

**Documentation**
- Updated `docs/FIELD_TYPES.md` with unique validation details
- Updated `examples/README.md` with RepeatingGroup testing commands
- Added `docs/FIELD_TYPES.md` (new file)
- Updated example forms with `unique = true` attribute

### Fixed

- **CLI Backend**: Fixed validation of duplicate items in add/edit operations
- **TUI Backend**: Fixed validation of duplicate items with error overlay feedback
- **Web Backend**: Fixed `has_unique` flag reading from field definition (was incorrectly scanning fragment fields)
- **Web Backend**: Fixed item counter not updating when adding/deleting items

### Changed

**Architecture**
- Each repeating group now maintains independent state via closure
- Removed ~600 lines of dead code in Web JavaScript
- Event handling now context-aware (finds correct repeating group controller)

**Examples**
- `examples/05-fragments/array-trackers.toml`: Added `unique = true` to UDP and HTTP tracker arrays
- `examples/07-nickel-generation/arrays-form.toml`: Added `unique = true` to all RepeatingGroup fields

### Technical Notes

- Duplicate detection compares ALL field values when `unique = true`
- Works consistently across CLI, TUI, and Web backends
- Backwards compatible: repeating groups without `unique = true` unaffected
- max_items limit already enforced in all backends (no changes needed)

### Testing

- All 174 unit tests passing
- No clippy warnings
- Build verified with `--all-features` flag
- Manual testing in Web backend: duplicate detection working correctly
- Item counter updates verified on add/delete operations