# UnifiedFiler v1.9.2 Notes

## Purpose

v1.9.2 continues from v1.9.1 and focuses on practical stability for Google Drive and large files. The main target is to avoid expensive full-tree redraws and prevent preview-related memory or download problems.

## Changes

- Tree expand/collapse now updates the clicked branch in place instead of rebuilding the whole tree.
- Folder create, folder rename, folder delete, copy/move, and drag/drop operations refresh the file list and then update only affected tree branches where possible.
- Normal navigation still keeps `refreshTreeOnNavigation: false` by default.
- Added preview object URL lifecycle management in FileExplorer. Object URLs created for Image/PDF/HTML preview are revoked when selection changes, preview is refreshed, or the component is destroyed.
- Added `PreviewService.renderWithResources()` for Host code that wants explicit control over generated object URLs. Existing `render()` remains backward compatible.
- Added `enableLargePreviewGuard` option, default `true`, to avoid reading large preview targets when metadata size already exceeds `maxPreviewSize`.
- Added pre-read package size guard in PackageInfoService so large ZIP/native packages can be rejected before downloading/reading content when `entry.size` is available.
- Added `packagePreviewTooLarge` i18n text for English, Japanese, and Chinese.

## Recommended settings

```javascript
$('#explorer').fileExplorer({
  defaultStorage: 'googleDrive',
  treeStorageMode: 'all',
  refreshTreeOnNavigation: false,
  enableLargePreviewGuard: true,
  maxPreviewSize: 1024 * 1024,
  maxPackagePreviewSize: 20 * 1024 * 1024
});
```

For very large ZIP/native packages, Host applications should keep preview disabled or keep `maxPackagePreviewSize` low and open the file through a dedicated viewer only when the user explicitly requests it.