forward errors from ZXing

@@ -322,6 +322,15 @@ class MobileScannerWeb extends MobileScannerPlatform {
 
           _barcodesController.add(barcode);
         },
+        onError: (Object error) {
+          if (_barcodesController.isClosed) {
+            return;
+          }
+
+          _barcodesController.addError(error);
+        },
+        // Errors are handled gracefully by forwarding them.
+        cancelOnError: false,
       );
 
       final bool hasTorch = await _barcodeReader?.hasTorch() ?? false;

@@ -3,6 +3,7 @@ import 'dart:js_interop';
 import 'dart:ui';
 
 import 'package:mobile_scanner/src/enums/barcode_format.dart';
+import 'package:mobile_scanner/src/mobile_scanner_exception.dart';
 import 'package:mobile_scanner/src/objects/barcode_capture.dart';
 import 'package:mobile_scanner/src/objects/start_options.dart';
 import 'package:mobile_scanner/src/web/barcode_reader.dart';
@@ -10,6 +11,7 @@ import 'package:mobile_scanner/src/web/javascript_map.dart';
 import 'package:mobile_scanner/src/web/media_track_constraints_delegate.dart';
 import 'package:mobile_scanner/src/web/zxing/result.dart';
 import 'package:mobile_scanner/src/web/zxing/zxing_browser_multi_format_reader.dart';
+import 'package:mobile_scanner/src/web/zxing/zxing_exception.dart';
 import 'package:web/web.dart' as web;
 
 /// A barcode reader implementation that uses the ZXing library.
@@ -98,16 +100,23 @@ final class ZXingBarcodeReader extends BarcodeReader {
       _reader?.decodeContinuously.callAsFunction(
         _reader,
         _reader?.videoElement,
-        (Result? result, JSAny? error) {
-          if (controller.isClosed || result == null) {
+        (Result? result, ZXingException? error) {
+          if (controller.isClosed) {
             return;
           }
 
+          if (error != null) {
+            controller.addError(MobileScannerBarcodeException(error.message));
+            return;
+          }
+
+          if (result != null) {
             controller.add(
               BarcodeCapture(
                 barcodes: [result.toBarcode],
               ),
             );
+          }
         }.toJS,
       );
     };

+import 'dart:js_interop';
+
+/// The JS static interop class for the Result class in the ZXing library.
+///
+/// See also: https://github.com/zxing-js/library/blob/master/src/core/Exception.ts
+@JS('ZXing.Exception')
+extension type ZXingException._(JSObject _) implements JSObject {
+  /// The error message of the exception, if any.
+  external String? get message;
+}