Web platform support: Store, Box and queries on IndexedDB

.github/workflows/web-test.yml

@@ -0,0 +1,46 @@
+name: Web test
+
+# Runs the browser tests for the web implementation of objectbox
+# (objectbox/lib/src/web/, tests in web_test/) with dart2js and dart2wasm.
+# Avoid duplicate builds for pull requests, allow manual trigger.
+on:
+  push:
+    branches:
+      - main
+      - dev
+      - web-support
+  pull_request:
+  workflow_dispatch:
+
+# Minimal access by default
+permissions:
+  contents: read
+
+defaults:
+  run:
+    shell: bash
+
+env:
+  # Keep aligned with test.yml.
+  DART_VERSION: 3.12.1 # Available versions: https://dart.dev/get-dart/archive
+
+jobs:
+  web-test:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v7
+      - uses: dart-lang/setup-dart@v1
+        with:
+          sdk: ${{ env.DART_VERSION }}
+      - name: Install dependencies
+        working-directory: web_test
+        run: dart pub get
+      - name: Generate binding code
+        working-directory: web_test
+        run: dart run build_runner build
+      - name: Test with dart2js (Chrome)
+        working-directory: web_test
+        run: dart test -p chrome
+      - name: Test with dart2wasm (Chrome)
+        working-directory: web_test
+        run: dart test -p chrome -c dart2wasm

flutter_libs/lib/objectbox_flutter_libs.dart

@@ -1,39 +1,9 @@
 /// This package contains platform-specific native libraries for flutter.
 /// See the actual library implementation in package "objectbox".
-library objectbox_flutter_libs;
-
-import 'dart:io';
-
-import 'package:flutter/services.dart';
-import 'package:objectbox/objectbox.dart';
-import 'package:path_provider/path_provider.dart';
-
-/// Returns the default database directory inside this Flutter app's
-/// `getApplicationDocumentsDirectory()`.
 ///
-/// Note: on desktop platforms this returns a directory in the users documents
-/// directory. It is advised to not use this then and instead create a directory
-/// named specifically for your app.
-Future<Directory> defaultStoreDirectory() async => Directory(
-  '${(await getApplicationDocumentsDirectory()).path}/${Store.defaultDirectoryPath}',
-);
+/// On the web platform there are no native libraries; the web variant provides
+/// compatible no-op implementations so that generated code compiles.
+library;
 
-const _platform = MethodChannel("objectbox_flutter_libs");
-
-/// If your Flutter app runs on Android 6 (or older) devices, call this before
-/// using any ObjectBox APIs, to fix loading the native ObjectBox library.
-///
-/// If the device is running Android 6 (or older) this will try to load the
-/// native library using Java APIs. Afterwards, calling ObjectBox APIs should
-/// load the library successfully on the Dart/Flutter side.
-///
-/// See the [GitHub issue for details](https://github.com/objectbox/objectbox-dart/issues/369).
-Future<void> loadObjectBoxLibraryAndroidCompat() async {
-  if (!Platform.isAndroid) {
-    // To support calling this in multi-platform Flutter apps
-    // do nothing if not Android (plugins for other platforms do not
-    // implement method below).
-    return;
-  }
-  await _platform.invokeMethod<String>('loadObjectBoxLibrary');
-}
+export 'src/objectbox_flutter_libs_native.dart'
+    if (dart.library.js_interop) 'src/objectbox_flutter_libs_web.dart';

flutter_libs/lib/src/objectbox_flutter_libs_native.dart

@@ -0,0 +1,35 @@
+import 'dart:io';
+
+import 'package:flutter/services.dart';
+import 'package:objectbox/objectbox.dart';
+import 'package:path_provider/path_provider.dart';
+
+/// Returns the default database directory inside this Flutter app's
+/// `getApplicationDocumentsDirectory()`.
+///
+/// Note: on desktop platforms this returns a directory in the users documents
+/// directory. It is advised to not use this then and instead create a directory
+/// named specifically for your app.
+Future<Directory> defaultStoreDirectory() async => Directory(
+  '${(await getApplicationDocumentsDirectory()).path}/${Store.defaultDirectoryPath}',
+);
+
+const _platform = MethodChannel("objectbox_flutter_libs");
+
+/// If your Flutter app runs on Android 6 (or older) devices, call this before
+/// using any ObjectBox APIs, to fix loading the native ObjectBox library.
+///
+/// If the device is running Android 6 (or older) this will try to load the
+/// native library using Java APIs. Afterwards, calling ObjectBox APIs should
+/// load the library successfully on the Dart/Flutter side.
+///
+/// See the [GitHub issue for details](https://github.com/objectbox/objectbox-dart/issues/369).
+Future<void> loadObjectBoxLibraryAndroidCompat() async {
+  if (!Platform.isAndroid) {
+    // To support calling this in multi-platform Flutter apps
+    // do nothing if not Android (plugins for other platforms do not
+    // implement method below).
+    return;
+  }
+  await _platform.invokeMethod<String>('loadObjectBoxLibrary');
+}

flutter_libs/lib/src/objectbox_flutter_libs_web.dart

@@ -0,0 +1,22 @@
+import 'package:objectbox/objectbox.dart';
+
+/// Stand-in for `dart:io`'s `Directory` on the web platform, where there is no
+/// real file system. Only carries the [path] that generated `openStore()` code
+/// passes to the [Store] constructor, which uses it as a logical database
+/// name on web.
+class WebStoreDirectory {
+  /// The logical database name.
+  final String path;
+
+  /// Wrap a logical database name.
+  const WebStoreDirectory(this.path);
+}
+
+/// Returns the default database location on web: there are no directories,
+/// so this is just [Store.defaultDirectoryPath] used as a logical name.
+Future<WebStoreDirectory> defaultStoreDirectory() async =>
+    const WebStoreDirectory(Store.defaultDirectoryPath);
+
+/// Does nothing on web (there is no native library to load). See the native
+/// variant of this function for details.
+Future<void> loadObjectBoxLibraryAndroidCompat() async {}

generator/lib/src/code_chunks.dart

@@ -29,7 +29,7 @@ class CodeChunks {
 
     import 'dart:typed_data';
 
-    import 'package:flat_buffers/flat_buffers.dart' as fb;
+    import 'package:objectbox/flatbuffers.dart' as fb;
     import 'package:objectbox/internal.dart' as $obxInt; // generated code can access "internal" functionality
     import 'package:objectbox/objectbox.dart' as $obx;${pubspec?.obxFlutterImport}
 
@@ -85,14 +85,16 @@ class CodeChunks {
           bool queriesCaseSensitiveDefault = true,
           String? macosApplicationGroup})${obxFlutter ? ' async' : ''} {
         ${obxFlutter ? 'await loadObjectBoxLibraryAndroidCompat();' : ''}
-        return $obx.Store(getObjectBoxModel(),
+        final store = $obx.Store(getObjectBoxModel(),
             directory: directory${obxFlutter ? ' ?? (await defaultStoreDirectory()).path' : ''},
             maxDBSizeInKB: maxDBSizeInKB,
             maxDataSizeInKB: maxDataSizeInKB,
             fileMode: fileMode,
             maxReaders: maxReaders,
             queriesCaseSensitiveDefault: queriesCaseSensitiveDefault,
             macosApplicationGroup: macosApplicationGroup);
+        ${obxFlutter ? '// On web the store loads persisted data asynchronously.\n        await store.ready;' : ''}
+        return store;
     }''';
   }
 
@@ -114,20 +116,30 @@ class CodeChunks {
       lastIndexId: ${createIdUid(model.lastIndexId)},
       lastRelationId: ${createIdUid(model.lastRelationId)},
       lastSequenceId: ${createIdUid(model.lastSequenceId)},
-      retiredEntityUids: const ${model.retiredEntityUids},
-      retiredIndexUids: const ${model.retiredIndexUids},
-      retiredPropertyUids: const ${model.retiredPropertyUids},
-      retiredRelationUids: const ${model.retiredRelationUids},
+      retiredEntityUids: ${createUidList(model.retiredEntityUids)},
+      retiredIndexUids: ${createUidList(model.retiredIndexUids)},
+      retiredPropertyUids: ${createUidList(model.retiredPropertyUids)},
+      retiredRelationUids: ${createUidList(model.retiredRelationUids)},
       modelVersion: ${model.modelVersion},
       modelVersionParserMinimum: ${model.modelVersionParserMinimum},
       version: ${model.version});
     ''';
   }
 
   static String createIdUid(IdUid value) {
-    return 'const $obxInt.IdUid(${value.id}, ${value.uid})';
+    // Emitted as a string parsed at runtime: UIDs are 64-bit values that
+    // regularly exceed 2^53 and can't be written as integer literals in code
+    // that is compiled to JavaScript (dart2js). See issue #185 (web support).
+    return "$obxInt.IdUid.fromString('${value.id}:${value.uid}')";
   }
 
+  /// Like [createIdUid]: retired UID lists are 64-bit values emitted as
+  /// runtime-parsed strings so generated code compiles with dart2js.
+  static String createUidList(List<int> uids) =>
+      uids.isEmpty
+          ? 'const []'
+          : "[${uids.map((uid) => "int.parse('$uid')").join(', ')}]";
+
   static String createModelEntity(ModelEntity entity) {
     var additionalArgs = '';
     if (entity.externalName != null) {

objectbox/CHANGELOG.md

@@ -1,5 +1,58 @@
 ## latest
 
+* Web platform support, phase 3 ([#185](https://github.com/objectbox/objectbox-dart/issues/185)):
+  queries. `box.query()` now works on web: a pure-Dart evaluator over the
+  condition tree running against the in-memory records. Supported: all
+  property conditions (string with case-sensitivity flags, integer, double,
+  bool, date/dateNano, byte vector, string vector `containsElement`,
+  `isNull`/`notNull`, `oneOf`/`notOneOf`, `between`), and/or groups,
+  `order()` (descending, caseSensitive, nullsLast, nullsAsZero, unsigned),
+  offset/limit, `find`/`findFirst`/`findUnique`/`findIds`/`count`/`remove`/
+  `stream` (+ async variants), query parameters (`param()` with alias
+  support), property queries (min/max/sum/average/count/find with distinct
+  and case sensitivity), relation links (`link`, `backlink`, `linkMany`,
+  `backlinkMany`, nested links, `relationCount`), `watch()` streams, and
+  vector search (`nearestNeighborsF32` with `findWithScores`/
+  `findIdsWithScores`) evaluated as an exact brute-force scan - Euclidean
+  (squared), cosine and dot-product distances; Geo is not supported on web.
+  Note: on web queries scan the in-memory records; indexes are not used yet.
+* Web platform support, phase 2 ([#185](https://github.com/objectbox/objectbox-dart/issues/185)):
+  a working database on web. `Store` and `Box` are now fully functional in the
+  browser: an in-memory engine (keeping the synchronous ObjectBox API) that is
+  persisted to IndexedDB with a write-behind queue. Supported: all CRUD
+  operations and `PutMode` semantics, monotonic ID assignment, `@Unique`
+  enforcement (including `ConflictStrategy.replace`), `ToOne`/`ToMany`
+  relations and backlinks, `runInTransaction` with rollback on error,
+  `store.watch<T>()`/`entityChanges` streams, `Store.attach`, in-memory
+  databases via `memory:` directories, and persistence across sessions
+  (including the unique index and ID sequences). Not yet supported on web:
+  queries (phase 3), `Store.fromReference`, isolates (`runAsync` runs on the
+  same thread), Sync and Admin.
+  - New: `Store.ready`, a future that completes when the store has loaded its
+    persisted data; completes immediately on native platforms. The generated
+    `openStore()` of Flutter apps awaits it automatically; pure Dart apps on
+    web should `await store.ready` after constructing the store.
+  - Durability note: on web, writes are applied to memory synchronously and
+    flushed to IndexedDB within a microtask; a browser crash may lose the very
+    last writes. `Store.close()` flushes the queue.
+  - The minimum Dart SDK is now 3.4 (dart:js_interop / package:web).
+  - FlatBuffers on web use a vendored copy of `flat_buffers` with
+    JavaScript-safe 64-bit integer handling (dart2js does not support
+    `ByteData.get/setInt64`); native platforms keep using the
+    `flat_buffers` package unchanged via the new conditional export
+    `package:objectbox/flatbuffers.dart`, which generated code now imports.
+* Web platform support, phase 1 ([#185](https://github.com/objectbox/objectbox-dart/issues/185)):
+  the package (including code generated by `objectbox_generator` and the
+  `objectbox_flutter_libs` helpers) now compiles for the web platform, with both
+  dart2js and dart2wasm. There is no database implementation on web yet: all
+  database operations throw `UnsupportedError` for now. `Admin.isAvailable()`,
+  `Sync.isAvailable()` and `Store.isOpen()` return `false` on web so existing
+  guard code keeps working. Native platforms are unchanged.
+* Generator: emit model IDs/UIDs as `IdUid.fromString(...)` and retired UID
+  lists as runtime-parsed strings instead of integer literals, which cannot be
+  compiled to JavaScript for values above 2^53 (UIDs are random 64-bit
+  values).
+
 ## 5.3.2 (2026-05-20)
 
 * Update ObjectBox database for Flutter Linux/Windows, Dart Native apps to [5.3.2-2026-05-05](https://github.com/objectbox/objectbox-c/releases/tag/v5.3.2)

objectbox/lib/flatbuffers.dart

@@ -0,0 +1,10 @@
+/// The FlatBuffers implementation used by ObjectBox and its generated code.
+///
+/// On native platforms this is `package:flat_buffers` as-is. On web it is a
+/// vendored copy with JavaScript-safe 64-bit integer handling, because
+/// dart2js does not support `ByteData.get/setInt64` (see
+/// `src/web/flatbuffers/`).
+library;
+
+export 'package:flat_buffers/flat_buffers.dart'
+    if (dart.library.js_interop) 'src/web/flatbuffers/flat_buffers.dart';

objectbox/lib/internal.dart

@@ -1,13 +1,15 @@
 /// This library serves as an entrypoint for generated code and objectbox tools.
 /// Don't import into your own code, use 'objectbox.dart' instead.
-library objectbox_internal;
+library;
 
+// Note: OBXVectorDistanceType and OBXHnswFlags are now exported via
+// modelinfo/index.dart (enums.dart) instead of the ffigen bindings, and
+// InternalStoreAccess via the platform-conditional store facade, so that this
+// library never pulls dart:ffi into a web build.
 export 'src/modelinfo/index.dart';
 export 'src/native/bindings/flatbuffers_readers.dart';
 export 'src/native/bindings/flexbuffers.dart';
-export 'src/native/bindings/objectbox_c.dart'
-    show OBXVectorDistanceType, OBXHnswFlags;
-export 'src/native/store.dart' show InternalStoreAccess;
 export 'src/relations/info.dart';
 export 'src/relations/to_many.dart'
     show InternalToManyAccess, InternalToManyTestAccess;
+export 'src/store.dart' show InternalStoreAccess;

objectbox/lib/objectbox.dart

@@ -2,14 +2,13 @@
 /// with strong ACID semantics.
 ///
 /// Read the [Getting Started](https://docs.objectbox.io/getting-started) guide.
-library objectbox;
+library;
 
 export 'src/admin.dart' show Admin;
 export 'src/annotations.dart';
 export 'src/box.dart' show Box, PutMode;
 export 'src/common.dart';
 export 'src/modelinfo/enums.dart' show OBXSyncFlags;
-export 'src/native/query/vector_search_results.dart';
 export 'src/query.dart'
     show
         Query,
@@ -55,3 +54,4 @@ export 'src/sync.dart'
         SyncState,
         SyncLoginEvent;
 export 'src/transaction.dart' show TxMode;
+export 'src/vector_search_results.dart';

objectbox/lib/src/admin.dart

@@ -1 +1 @@
-export 'native/admin.dart' if (dart.library.html) 'web/admin.dart';
+export 'native/admin.dart' if (dart.library.js_interop) 'web/admin.dart';

objectbox/lib/src/box.dart

@@ -1 +1,13 @@
-export 'native/box.dart' if (dart.library.html) 'web/box.dart';
+export 'native/box.dart' if (dart.library.js_interop) 'web/box.dart';
+
+/// Box put (write) mode.
+enum PutMode {
+  /// Insert (if given object's ID is zero) or update an existing object.
+  put,
+
+  /// Insert a new object.
+  insert,
+
+  /// Update an existing object, fails if the given ID doesn't exist.
+  update,
+}

objectbox/lib/src/model.dart

@@ -1 +1 @@
-export 'native/model.dart' if (dart.library.html) 'web/model.dart';
+export 'native/model.dart' if (dart.library.js_interop) 'web/model.dart';

objectbox/lib/src/modelinfo/entity_definition.dart

@@ -1,7 +1,6 @@
-import 'dart:ffi';
 import 'dart:typed_data';
 
-import 'package:flat_buffers/flat_buffers.dart' as fb;
+import '../../flatbuffers.dart' as fb;
 
 import '../relations/info.dart';
 import '../relations/to_many.dart';
@@ -31,15 +30,4 @@ class EntityDefinition<T> {
       required this.toManyRelations});
 
   Type type() => T;
-
-  /// Shortcut that creates a [ByteData] view and passes it to [objectFromFB].
-  T objectFromData(Store store, Pointer<Uint8> data, int size) {
-    // There has been a performance improvement in the past using memcpy for
-    // small buffers, but this is not longer faster than asTypedList.
-    // See /benchmark/bin/native_pointers.dart.
-    final uInt8List = data.asTypedList(size);
-    final byteData =
-        ByteData.view(uInt8List.buffer, uInt8List.offsetInBytes, size);
-    return objectFromFB(store, byteData);
-  }
 }