#3180. Add more tests for JS interop. Part 2. (#3274)

Add more tests for JS interop. Part 2.

Author: sgrekhov

LibTest/js_interop/JS/js_A01_t02.dart

@@ -25,7 +25,21 @@ external int f2({required int v});
 // [analyzer] unspecified
 // [web] unspecified
 
+@JS()
+external int f3(int id, {int v});
+//                           ^
+// [analyzer] unspecified
+// [web] unspecified
+
+@JS("foo")
+external int f4(int id, {required int v});
+//                                    ^
+// [analyzer] unspecified
+// [web] unspecified
+
 main() {
   print(f1());
   print(f2(v: 1));
+  print(f3(3, v: 1));
+  print(f4(4, v: 1));
 }

LibTest/js_interop/interop_A01_t09.dart

@@ -0,0 +1,56 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion Within an interop type, you can declare several different types
+/// of external interop members:
+/// - Constructors. When called, constructors with only positional parameters
+///   create a new JS object whose constructor is defined by the name of the
+///   extension type using `new`.
+///
+/// @description Check that it is a compile-time error to tear-off a constructor
+/// of a JS interop type.
+/// @author [email protected]
+
+import 'dart:js_interop';
+
+extension type ET._(JSObject v) implements JSObject {
+  external ET(int id, String? name);
+  external ET.fromId(int id);
+  ET.create(this.v);
+}
+
+@JS("ET")
+extension type ET2.p(JSObject v) implements JSObject {
+  external factory ET2(int id, String? name);
+  external factory ET2.fromId(int id);
+  factory ET2.create(JSObject v) = ET2.p;
+}
+
+main() {
+  var etNew = ET.new;
+//            ^^^^^^
+// [analyzer] unspecified
+// [web] unspecified
+
+  var etFromId = ET.fromId;
+//               ^^^^^^^^^
+// [analyzer] unspecified
+// [web] unspecified
+
+  var etPrimary1 = ET._; // Ok, not external constructor
+  var etPrimary2 = ET.create;
+
+  var et2New = ET2.new;
+//             ^^^^^^^
+// [analyzer] unspecified
+// [web] unspecified
+
+  var et2fromId = ET2.fromId;
+//                ^^^^^^^^^^
+// [analyzer] unspecified
+// [web] unspecified
+
+  var et2Primary1 = ET2.p; // Ok, not external constructor
+  var et2Primary2 = ET2.create;
+}

LibTest/js_interop/interop_A01_t10.dart

@@ -0,0 +1,62 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion Within an interop type, you can declare several different types
+/// of external interop members:
+/// - Constructors. When called, constructors with only positional parameters
+///   create a new JS object whose constructor is defined by the name of the
+///   extension type using `new`.
+///
+/// @description Check that a constructor of a JS interop type with positional
+/// parameters when called creates a new JS object whose constructor is defined
+/// by the name of the extension type using `new`. Test the case when JS type
+/// contains a static member with the same name.
+/// @author [email protected]
+
+import 'dart:js_interop';
+import '../../Utils/expect.dart';
+import 'js_utils.dart';
+
+extension type ET._(JSObject _) implements JSObject {
+  external ET.create(int id, String? name);
+
+  external int? get id;
+  external String? get name;
+}
+
+@JS("ET")
+extension type ET2._(JSObject _) implements JSObject {
+  external factory ET2.create(int id, String? name);
+
+  external int? get id;
+  external String? get name;
+}
+
+main() {
+  eval(r'''
+    class ET {
+      constructor(id, name) {
+        this._id = id;
+        this._name = name;
+      }
+      static create(id, name) {
+        return 42;
+      }
+      get id() {
+        return this._id;
+      }
+      get name() {
+        return this._name;
+      }
+    }
+    globalThis.ET = ET;
+  ''');
+  ET et1 = ET.create(1, "one");
+  Expect.equals(1, et1.id);
+  Expect.equals("one", et1.name);
+
+  ET2 et2 = ET2.create(2, "two");
+  Expect.equals(2, et2.id);
+  Expect.equals("two", et2.name);
+}

LibTest/js_interop/interop_A01_t11.dart

@@ -0,0 +1,53 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion Within an interop type, you can declare several different types
+/// of external interop members:
+/// - Constructors. When called, constructors with only positional parameters
+///   create a new JS object whose constructor is defined by the name of the
+///   extension type using `new`.
+///
+/// @description Check that it is a warning if an external constructor of JS
+/// interop type is annotated with `@JS()` annotation.
+/// @author [email protected]
+/// @issue 61274
+
+import 'dart:js_interop';
+import '../../Utils/expect.dart';
+import 'js_utils.dart';
+
+extension type ET._(JSObject _) implements JSObject {
+  @JS("create")
+  external ET(int id, String? name);
+//         ^^
+// [analyzer] unspecified
+// [web] unspecified
+
+  @JS("fromId")
+  external ET.f(int id);
+//         ^^^^
+// [analyzer] unspecified
+// [web] unspecified
+
+}
+
+@JS("ET")
+extension type ET2._(JSObject _) implements JSObject {
+  @JS("")
+  external ET2(int id, String? name);
+//         ^^^
+// [analyzer] unspecified
+// [web] unspecified
+
+  @JS(null)
+  external ET2.f(int id);
+//         ^^^^^
+// [analyzer] unspecified
+// [web] unspecified
+}
+
+main() {
+  print(ET);
+  print(ET2);
+}

LibTest/js_interop/interop_A01_t12.dart

@@ -0,0 +1,65 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion Within an interop type, you can declare several different types
+/// of external interop members:
+/// - Constructors. When called, constructors with only positional parameters
+///   create a new JS object whose constructor is defined by the name of the
+///   extension type using `new`.
+///
+/// @description Check that default values of an external constructor of a JS
+/// interop type are ignored.
+/// @author [email protected]
+
+import 'dart:js_interop';
+import '../../Utils/expect.dart';
+import 'js_utils.dart';
+
+extension type ET._(JSObject _) implements JSObject {
+  external ET([int? id = 0, String? name = "default"]);
+
+  external int? get id;
+  external String? get name;
+}
+
+@JS("ET")
+extension type ET2._(JSObject _) implements JSObject {
+  external factory ET2([int? id = 0, String? name = "default"]);
+
+  external int? get id;
+  external String? get name;
+}
+
+main() {
+  eval(r'''
+    class ET {
+      constructor(id, name) {
+        this._id = id;
+        this._name = name;
+      }
+      get id() {
+        return this._id;
+      }
+      get name() {
+        return this._name;
+      }
+    }
+    globalThis.ET = ET;
+  ''');
+  ET et1 = ET();
+  Expect.isNull(et1.id);
+  Expect.isNull(et1.name);
+
+  ET et2 = ET(2);
+  Expect.equals(2, et2.id);
+  Expect.isNull(et2.name);
+
+  ET2 et3 = ET2();
+  Expect.isNull(et3.id);
+  Expect.isNull(et3.name);
+
+  ET2 et4 = ET2(4);
+  Expect.equals(4, et4.id);
+  Expect.isNull(et4.name);
+}

LibTest/js_interop/interop_A06_t01.dart

@@ -0,0 +1,79 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion You can also write external members in extensions of interop
+/// types.
+///
+/// @description Check that external members in extensions of interop types are
+/// allowed and work as expected.
+/// @author [email protected]
+
+import 'dart:js_interop';
+import '../../Utils/expect.dart';
+import 'js_utils.dart';
+
+extension type ET._(JSObject _) implements JSObject {
+  external ET(int id, String? name);
+
+  external int get id;
+}
+
+extension on ET {
+  external String? get name;
+  external void set name(String? value);
+  external int answer();
+}
+
+@JS("ET")
+extension type ET2._(JSObject _) implements JSObject {
+  external factory ET2(int id, String? name);
+
+  external int get id;
+}
+
+extension Ext on ET2 {
+  @JS("name")
+  external String? get getName;
+  @JS("name")
+  external void set setName(String? value);
+  @JS("answer")
+  external int getAnswer();
+}
+
+main() {
+  eval(r'''
+    class ET {
+      constructor(id, name) {
+        this._id = id;
+        this._name = name;
+      }
+      get id() {
+        return this._id;
+      }
+      get name() {
+        return this._name;
+      }
+      set name(v) {
+        return this._name = v;
+      }
+      answer() {
+        return 42;
+      }
+    }
+    globalThis.ET = ET;
+  ''');
+  ET et1 = ET(1, "one");
+  Expect.equals(1, et1.id);
+  Expect.equals("one", et1.name);
+  et1.name = "1";
+  Expect.equals("1", et1.name);
+  Expect.equals(42, et1.answer());
+
+  ET2 et2 = ET2(2, "two");
+  Expect.equals(2, et2.id);
+  Expect.equals("two", et2.getName);
+  et2.setName = "2";
+  Expect.equals("2", et2.getName);
+  Expect.equals(42, et2.getAnswer());
+}