#3180. Add tests for JS interop type constructors (#3272)

Add tests for JS interop type constructors

Author: sgrekhov

LibTest/js_interop/interop_A01_t01.dart

@@ -0,0 +1,68 @@
+// 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`.
+/// @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 ET.fromId(int id);
+
+  external int get id;
+  external String? get name;
+}
+
+@JS("ET")
+extension type ET2._(JSObject _) implements JSObject {
+  external factory ET2(int id, String? name);
+  external factory ET2.fromId(int id);
+
+  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(1, "one");
+  Expect.equals(1, et1.id);
+  Expect.equals("one", et1.name);
+
+  ET et2 = ET.fromId(2);
+  Expect.equals(2, et2.id);
+  Expect.isNull(et2.name);
+
+  ET2 et3 = ET2(3, "three");
+  Expect.equals(3, et3.id);
+  Expect.equals("three", et3.name);
+
+  ET2 et4 = ET2.fromId(4);
+  Expect.equals(4, et4.id);
+  Expect.isNull(et4.name);
+}

LibTest/js_interop/interop_A01_t02.dart

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+// 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 excessive
+/// positional parameter is ignored by JS.
+/// @author [email protected]
+
+import 'dart:js_interop';
+import '../../Utils/expect.dart';
+import 'js_utils.dart';
+
+extension type ET._(JSObject _) implements JSObject {
+  external ET.withDescription(int id, String? name, String description);
+
+  external int get id;
+  external String? get name;
+}
+
+@JS("ET")
+extension type ET2._(JSObject _) implements JSObject {
+  external ET2.withDescription(int id, String? name, String description);
+
+  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.withDescription(1, "one", "Description");
+  Expect.equals(1, et1.id);
+  Expect.equals("one", et1.name);
+
+  ET2 et2 = ET2.withDescription(2, "two", "Description");
+  Expect.equals(2, et2.id);
+  Expect.equals("two", et2.name);
+}

LibTest/js_interop/interop_A01_t03.dart

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+// 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 not an error if a constructor of a JS
+/// interop type has no parameters.
+/// @author [email protected]
+
+import 'dart:js_interop';
+import '../../Utils/expect.dart';
+import 'js_utils.dart';
+
+extension type ET._(JSObject _) implements JSObject {
+  external ET.empty();
+  external int? get id;
+  external String? get name;
+}
+
+main() {
+  eval(r'''
+    class ET {
+      constructor(id, name) {
+        if (id == null) {
+          this._id = 0;
+        } else { 
+          this._id = id;
+        }
+        this._name = name;
+      }
+      get id() {
+        return this._id;
+      }
+      get name() {
+        return this._name;
+      }
+    }
+    globalThis.ET = ET;
+  ''');
+
+  ET et1 = ET.empty();
+  Expect.equals(0, et1.id);
+  Expect.isNull(et1.name);
+
+}

LibTest/js_interop/interop_A01_t04.dart

@@ -0,0 +1,34 @@
+// 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 if a constructor of a
+/// JS interop type contains both named and positional parameters.
+/// @author [email protected]
+
+import 'dart:js_interop';
+
+extension type ET1._(JSObject _) implements JSObject {
+  external ET1.withDescription(int id, String? name, {String description});
+//                                 ^^
+// [analyzer] unspecified
+// [web] unspecified
+}
+
+extension type ET2._(JSObject _) implements JSObject {
+  external factory ET2(int id, String? name, {String description});
+//                         ^^
+// [analyzer] unspecified
+// [web] unspecified
+}
+
+main() {
+  print(ET1);
+  print(ET2);
+}

LibTest/js_interop/interop_A01_t05.dart

@@ -0,0 +1,60 @@
+// 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 invoking a constructor of a JS interop type creates
+/// a new JS object.
+/// @author [email protected]
+
+import 'dart:js_interop';
+import 'dart:js_interop_unsafe';
+import '../../Utils/expect.dart';
+import 'js_utils.dart';
+
+extension type ET._(JSObject _) implements JSObject {
+  external ET(int id, String? name);
+
+  external int get id;
+  external String? get name;
+}
+
+@JS("ET")
+extension type ET2._(JSObject _) implements JSObject {
+  external factory ET2(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;
+      }
+      get id() {
+        return this._id;
+      }
+      get name() {
+        return this._name;
+      }
+    }
+    globalThis.ET = ET;
+  ''');
+  globalContext["et1"] = ET(1, "one");
+  globalContext["et2"] = ET(1, "one");
+  eval("globalThis.res1 = globalThis.et1 == globalThis.et2;");
+  Expect.isFalse((globalContext["res1"] as JSBoolean).toDart);
+
+  globalContext["et3"] = ET2(2, "two");
+  globalContext["et4"] = ET2(2, "two");
+  eval("globalThis.res2 = globalThis.et3 == globalThis.et4;");
+  Expect.isFalse((globalContext["res2"] as JSBoolean).toDart);
+}

LibTest/js_interop/interop_A02_t01.dart

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+// 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:
+/// ...
+/// - Object literal constructors. It's sometimes useful to create a JS object
+///   literal that simply contains a number of properties and their values. In
+///   order to do this, declare a constructor with only named parameters, where
+///   the names of the parameters match the property names.
+///
+/// @description Check that a constructor of a JS interop type with named
+/// parameters creates a new JS object with all properties defined by the
+/// constructor.
+/// @author [email protected]
+
+import 'dart:js_interop';
+import 'dart:js_interop_unsafe';
+import '../../Utils/expect.dart';
+import 'js_utils.dart';
+
+extension type ET1._(JSObject _) implements JSObject {
+  external ET1({int id, String? name});
+  external ET1.fromId({int id});
+
+  external int get id;
+  external String? get name;
+}
+
+extension type ET2._(JSObject _) implements JSObject {
+  external factory ET2({int id, String? name});
+  external factory ET2.fromId({int id});
+
+  external int get id;
+  external String? get name;
+}
+
+main() {
+  globalContext["et1"] = ET1(id: 1, name: "one");
+  eval(r'''
+    globalThis.v1 = globalThis.et1.id;
+    globalThis.v2 = globalThis.et1.name;
+  ''');
+  Expect.equals(1, (globalContext["v1"] as JSNumber).toDartInt);
+  Expect.equals("one", (globalContext["v2"] as JSString).toDart);
+
+  globalContext["et2"] = ET1.fromId(id: 2);
+  eval(r'''
+    globalThis.v3 = globalThis.et2.id;
+    globalThis.v4 = globalThis.et2.name;
+  ''');
+  Expect.equals(2, (globalContext["v3"] as JSNumber).toDartInt);
+  Expect.isNull(globalContext["v4"]);
+
+  globalContext["et3"] = ET2(id: 3, name: "three");
+  eval(r'''
+    globalThis.v5 = globalThis.et3.id;
+    globalThis.v6 = globalThis.et3.name;
+  ''');
+  Expect.equals(3, (globalContext["v5"] as JSNumber).toDartInt);
+  Expect.equals("three", (globalContext["v6"] as JSString).toDart);
+
+  globalContext["et4"] = ET2.fromId(id: 4);
+  eval(r'''
+    globalThis.v7 = globalThis.et4.id;
+    globalThis.v8 = globalThis.et4.name;
+  ''');
+  Expect.equals(4, (globalContext["v7"] as JSNumber).toDartInt);
+  Expect.isNull(globalContext["v8"]);
+}

LibTest/js_interop/interop_A02_t02.dart

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+// 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:
+/// ...
+/// - Object literal constructors. It's sometimes useful to create a JS object
+///   literal that simply contains a number of properties and their values. In
+///   order to do this, declare a constructor with only named parameters, where
+///   the names of the parameters match the property names.
+///
+/// @description Check that invoking a constructor of a JS interop type creates
+/// a new JS object.
+/// @author [email protected]
+
+import 'dart:js_interop';
+import 'dart:js_interop_unsafe';
+import '../../Utils/expect.dart';
+import 'js_utils.dart';
+
+extension type ET1._(JSObject _) implements JSObject {
+  external ET1({int id, String? name});
+
+  external int get id;
+  external String? get name;
+}
+
+extension type ET2._(JSObject _) implements JSObject {
+  external factory ET2({int id, String? name});
+
+  external int get id;
+  external String? get name;
+}
+
+main() {
+  globalContext["et1"] = ET1(id: 1, name: "one");
+  globalContext["et2"] = ET1(id: 1, name: "one");
+  eval("globalThis.res1 = globalThis.et1 == globalThis.et2;");
+  Expect.isFalse((globalContext["res1"] as JSBoolean).toDart);
+
+  globalContext["et3"] = ET2(id: 2, name: "two");
+  globalContext["et4"] = ET2(id: 2, name: "two");
+  eval("globalThis.res2 = globalThis.et3 == globalThis.et4;");
+  Expect.isFalse((globalContext["res2"] as JSBoolean).toDart);
+}