fix(ext/web): define Symbol.toStringTag on interface prototypes

ext/fetch/27_eventsource.js

@@ -19,6 +19,8 @@ const {
   StringPrototypeStartsWith,
   StringPrototypeToLowerCase,
   SymbolFor,
+  ObjectDefineProperty,
+  SymbolToStringTag,
 } = primordials;
 
 const webidl = core.loadExtScript("ext:deno_webidl/00_webidl.js");
@@ -416,6 +418,13 @@ class EventSource extends EventTarget {
 }
 
 const EventSourcePrototype = EventSource.prototype;
+ObjectDefineProperty(EventSourcePrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "EventSource",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 ObjectDefineProperties(EventSource, {
   CONNECTING: {

ext/web/01_broadcast_channel.js

@@ -21,6 +21,8 @@ const {
   Symbol,
   SymbolFor,
   Uint8Array,
+  ObjectDefineProperty,
+  SymbolToStringTag,
 } = primordials;
 
 const webidl = core.loadExtScript("ext:deno_webidl/00_webidl.js");
@@ -223,6 +225,13 @@ class BroadcastChannel extends EventTarget {
 defineEventHandler(BroadcastChannel.prototype, "message");
 defineEventHandler(BroadcastChannel.prototype, "messageerror");
 const BroadcastChannelPrototype = BroadcastChannel.prototype;
+ObjectDefineProperty(BroadcastChannelPrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "BroadcastChannel",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 return { BroadcastChannel, refBroadcastChannel };
 })();

ext/web/02_event.js

@@ -1223,10 +1223,16 @@ class ErrorEvent extends Event {
   }
 
   // TODO(lucacasonato): remove when this interface is spec aligned
-  [SymbolToStringTag] = "ErrorEvent";
 }
 
 const ErrorEventPrototype = ErrorEvent.prototype;
+ObjectDefineProperty(ErrorEventPrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "ErrorEvent",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 defineEnumerableProps(ErrorEvent, [
   "message",
@@ -1288,6 +1294,13 @@ class CloseEvent extends Event {
 }
 
 const CloseEventPrototype = CloseEvent.prototype;
+ObjectDefineProperty(CloseEventPrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "CloseEvent",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 // Lazy reference to MessagePort.prototype - 13_message_port.js depends on
 // this module, so the script can't be loaded at definition time without
@@ -1444,10 +1457,16 @@ class MessageEvent extends Event {
   }
 
   // TODO(lucacasonato): remove when this interface is spec aligned
-  [SymbolToStringTag] = "MessageEvent";
 }
 
 const MessageEventPrototype = MessageEvent.prototype;
+ObjectDefineProperty(MessageEventPrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "MessageEvent",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 class CustomEvent extends Event {
   #detail = null;
@@ -1482,10 +1501,16 @@ class CustomEvent extends Event {
   }
 
   // TODO(lucacasonato): remove when this interface is spec aligned
-  [SymbolToStringTag] = "CustomEvent";
 }
 
 const CustomEventPrototype = CustomEvent.prototype;
+ObjectDefineProperty(CustomEventPrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "CustomEvent",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 ReflectDefineProperty(CustomEvent.prototype, "detail", {
   __proto__: null,
@@ -1520,10 +1545,16 @@ class ProgressEvent extends Event {
   }
 
   // TODO(lucacasonato): remove when this interface is spec aligned
-  [SymbolToStringTag] = "ProgressEvent";
 }
 
 const ProgressEventPrototype = ProgressEvent.prototype;
+ObjectDefineProperty(ProgressEventPrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "ProgressEvent",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 class PromiseRejectionEvent extends Event {
   #promise = null;
@@ -1575,10 +1606,16 @@ class PromiseRejectionEvent extends Event {
   }
 
   // TODO(lucacasonato): remove when this interface is spec aligned
-  [SymbolToStringTag] = "PromiseRejectionEvent";
 }
 
 const PromiseRejectionEventPrototype = PromiseRejectionEvent.prototype;
+ObjectDefineProperty(PromiseRejectionEventPrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "PromiseRejectionEvent",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 defineEnumerableProps(PromiseRejectionEvent, [
   "promise",

runtime/js/11_workers.js

@@ -27,6 +27,7 @@ const {
   SymbolFor,
   SymbolIterator,
   SymbolToStringTag,
+  ObjectDefineProperty,
 } = primordials;
 
 const EMPTY_OPTIONS = ObjectFreeze(ObjectSetPrototypeOf({}, null));
@@ -382,10 +383,16 @@ class Worker extends EventTarget {
     );
   }
 
-  [SymbolToStringTag] = "Worker";
 }
 
 const WorkerPrototype = Worker.prototype;
+ObjectDefineProperty(WorkerPrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "Worker",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 defineEventHandler(Worker.prototype, "error");
 defineEventHandler(Worker.prototype, "message");

runtime/js/98_global_scope_window.js

@@ -12,6 +12,8 @@ const {
   SymbolFor,
   StringPrototypeToUpperCase,
   StringPrototypeSlice,
+  ObjectDefineProperty,
+  SymbolToStringTag,
 } = primordials;
 
 const location = core.loadExtScript("ext:deno_web/12_location.js");
@@ -203,6 +205,13 @@ ObjectDefineProperties(Navigator.prototype, {
   },
 });
 const NavigatorPrototype = Navigator.prototype;
+ObjectDefineProperty(NavigatorPrototype, SymbolToStringTag, {
+  __proto__: null,
+  value: "Navigator",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
 
 const mainRuntimeGlobalProperties = {
   Location: location.locationConstructorDescriptor,

tests/unit/event_test.ts

@@ -41,6 +41,54 @@ Deno.test(function eventSubclassWithReadOnlyToStringTag() {
   assertEquals(Object.hasOwn(event, Symbol.toStringTag), false);
 });
 
+Deno.test(function interfacePrototypesHaveToStringTag() {
+  const interfaces = [
+    BroadcastChannel,
+    CloseEvent,
+    CustomEvent,
+    ErrorEvent,
+    EventSource,
+    MessageEvent,
+    Navigator,
+    ProgressEvent,
+    PromiseRejectionEvent,
+    Worker,
+  ];
+  for (const iface of interfaces) {
+    const descriptor = Object.getOwnPropertyDescriptor(
+      iface.prototype,
+      Symbol.toStringTag,
+    );
+    assertEquals(descriptor, {
+      value: iface.name,
+      writable: false,
+      enumerable: false,
+      configurable: true,
+    }, iface.name);
+  }
+
+  const event = new CustomEvent("test");
+  assertEquals(Object.hasOwn(event, Symbol.toStringTag), false);
+  assertEquals(
+    Object.prototype.toString.call(event),
+    "[object CustomEvent]",
+  );
+  assertEquals(
+    Object.prototype.toString.call(navigator),
+    "[object Navigator]",
+  );
+
+  class MyEvent extends CustomEvent<unknown> {
+    get [Symbol.toStringTag]() {
+      return "MyEvent";
+    }
+  }
+  assertEquals(
+    Object.prototype.toString.call(new MyEvent("test")),
+    "[object MyEvent]",
+  );
+});
+
 Deno.test(function eventComposedPathSuccess() {
   const type = "click";
   const event = new Event(type);