fix: preserve original HEIC/HEIF files and treat them as file type

- Prevent HEIC/HEIF to JPEG conversion in react-native-image-picker by setting quality: 1
- Detect HEIC files by reading magic bytes (ftyp box) and correct misidentified MIME type/extension
- Treat HEIC/HEIF as file type instead of image (not universally supported for inline display)
- Add test cases for HEIC/HEIF file type detection

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: bang9

packages/uikit-react-native/src/platform/createFileService.native.ts

@@ -44,6 +44,33 @@ function getAndroidStoragePermissionsByAPILevel(permissionModule: typeof Permiss
   ];
 }
 
+// HEIC/HEIF brands defined in ISO Base Media File Format
+const HEIC_BRANDS = ['heic', 'heix', 'hevc', 'hevx', 'heim', 'heis', 'hevm', 'hevs', 'mif1', 'msf1'];
+
+/**
+ * Detects if a file is HEIC/HEIF by reading its magic bytes.
+ * HEIC/HEIF files use ISOBMFF container format with 'ftyp' box and specific brand codes.
+ */
+async function detectHeicFromUri(uri: string): Promise<boolean> {
+  try {
+    const response = await fetch(uri);
+    const buffer = await response.arrayBuffer();
+    const bytes = new Uint8Array(buffer.slice(0, 24));
+
+    // Check for 'ftyp' at bytes 4-7
+    if (bytes[4] === 0x66 && bytes[5] === 0x74 && bytes[6] === 0x79 && bytes[7] === 0x70) {
+      // Read major brand at bytes 8-11
+      const majorBrand = String.fromCharCode(bytes[8], bytes[9], bytes[10], bytes[11]).toLowerCase();
+      if (HEIC_BRANDS.includes(majorBrand)) {
+        return true;
+      }
+    }
+    return false;
+  } catch {
+    return false;
+  }
+}
+
 const createNativeFileService = ({
   imagePickerModule,
   documentPickerModule,
@@ -151,6 +178,11 @@ const createNativeFileService = ({
       const response = await imagePickerModule.launchImageLibrary({
         presentationStyle: 'fullScreen',
         selectionLimit,
+        assetRepresentationMode: 'current',
+        // NOTE: quality must be set to 1 to prevent HEIC/HEIF to JPEG conversion.
+        // Without this, the native code's condition (quality >= 0 && quality < 1) becomes true
+        // when quality is undefined (floatValue returns 0.0), triggering unwanted JPEG conversion.
+        quality: 1,
         mediaType: (() => {
           switch (options?.mediaType) {
             case 'photo':
@@ -170,11 +202,28 @@ const createNativeFileService = ({
         return null;
       }
 
-      return Promise.all(
-        (response.assets || [])
-          .slice(0, selectionLimit)
-          .map(({ fileName: name, fileSize: size, type, uri }) => normalizeFile({ uri, size, name, type })),
+      // Correct HEIC/HEIF file extension and MIME type that react-native-image-picker misidentifies as JPEG
+      const correctedAssets = await Promise.all(
+        (response.assets || []).slice(0, selectionLimit).map(async (asset) => {
+          const { fileName, fileSize: size, type: originalType, uri } = asset;
+          let name = fileName;
+          let type = originalType;
+
+          if (uri && (type === 'image/jpeg' || type === 'image/jpg' || name?.toLowerCase().endsWith('.jpg'))) {
+            const isHeic = await detectHeicFromUri(uri);
+            if (isHeic) {
+              type = 'image/heic';
+              if (name) {
+                name = name.replace(/\.jpe?g$/i, '.heic');
+              }
+            }
+          }
+
+          return { uri, size, name, type };
+        }),
       );
+
+      return Promise.all(correctedAssets.map(({ uri, size, name, type }) => normalizeFile({ uri, size, name, type })));
     }
 
     async openDocument(options?: OpenDocumentOptions): Promise<FilePickerResponse> {

packages/uikit-utils/src/__tests__/shared/file.test.ts

@@ -25,6 +25,9 @@ describe('getFileType', function () {
     expect(getFileType('application/zip')).toBe('file');
     expect(getFileType('application/x-gzip')).toBe('file');
     expect(getFileType('text/plain')).toBe('file');
+    // HEIC/HEIF should be treated as file (not universally supported for inline display)
+    expect(getFileType('image/heic')).toBe('file');
+    expect(getFileType('image/heif')).toBe('file');
   });
 
   it('should return the proper file type with file extension', () => {

packages/uikit-utils/src/shared/file.ts

@@ -44,15 +44,21 @@ const EXTENSION_MIME_MAP = {
 export const imageExtRegex = /jpeg|jpg|png|webp|gif/i;
 export const audioExtRegex = /3gp|aac|aax|act|aiff|flac|gsm|m4a|m4b|m4p|tta|wma|mp3|webm|wav|ogg/i;
 export const videoExtRegex = /mov|vod|mp4|avi|mpeg|ogv/i;
+// HEIC/HEIF should be treated as file, not image (not universally supported for inline display)
+export const nonImageMimeSubtypes = /heic|heif/i;
 export const getFileType = (extensionOrType: string) => {
   const lowerCased = extensionOrType.toLowerCase();
 
   // mime type
   if (lowerCased.indexOf('/') > -1) {
-    const type = lowerCased.split('/')[0];
+    const [type, subtype] = lowerCased.split('/');
     if (type === 'video') return 'video';
     if (type === 'audio') return 'audio';
-    if (type === 'image') return 'image';
+    if (type === 'image') {
+      // HEIC/HEIF are not universally supported, treat as file
+      if (subtype?.match(nonImageMimeSubtypes)) return 'file';
+      return 'image';
+    }
     return 'file';
   }