1 files changed, 33 insertions, 4 deletions

diff --git a/js/src/builtin/SymbolObject.cpp b/js/src/builtin/SymbolObject.cpp
index cf48402d6..8fa860ef3 100644
--- a/js/src/builtin/SymbolObject.cpp
+++ b/js/src/builtin/SymbolObject.cpp
@@ -33,6 +33,7 @@ SymbolObject::create(JSContext* cx, JS::HandleSymbol symbol)
 }
 
 const JSPropertySpec SymbolObject::properties[] = {
+    JS_PSG("description", descriptionGetter, 0),
     JS_PS_END
 };
 
@@ -52,17 +53,17 @@ const JSFunctionSpec SymbolObject::staticMethods[] = {
 JSObject*
 SymbolObject::initClass(JSContext* cx, HandleObject obj)
 {
-    Rooted<GlobalObject*> global(cx, &obj->as<GlobalObject>());
+    Handle<GlobalObject*> global = obj.as<GlobalObject>();
 
     // This uses &JSObject::class_ because: "The Symbol prototype object is an
     // ordinary object. It is not a Symbol instance and does not have a
     // [[SymbolData]] internal slot." (ES6 rev 24, 19.4.3)
-    RootedObject proto(cx, global->createBlankPrototype<PlainObject>(cx));
+    RootedObject proto(cx, GlobalObject::createBlankPrototype<PlainObject>(cx, global));
     if (!proto)
         return nullptr;
 
-    RootedFunction ctor(cx, global->createConstructor(cx, construct,
-                                                      ClassName(JSProto_Symbol, cx), 0));
+    RootedFunction ctor(cx, GlobalObject::createConstructor(cx, construct,
+                                                            ClassName(JSProto_Symbol, cx), 0));
     if (!ctor)
         return nullptr;
 
@@ -227,6 +228,34 @@ SymbolObject::toPrimitive(JSContext* cx, unsigned argc, Value* vp)
     return CallNonGenericMethod<IsSymbol, valueOf_impl>(cx, args);
 }
 
+// ES2019 Stage 4 Draft / November 28, 2018
+// Symbol description accessor
+// See: https://tc39.github.io/proposal-Symbol-description/
+bool
+SymbolObject::descriptionGetter_impl(JSContext* cx, const CallArgs& args)
+{
+    // Get symbol object pointer.
+    HandleValue thisv = args.thisv();
+    MOZ_ASSERT(IsSymbol(thisv));
+    Rooted<Symbol*> sym(cx, thisv.isSymbol()
+                            ? thisv.toSymbol()
+                            : thisv.toObject().as<SymbolObject>().unbox());
+
+    // Return the symbol's description if present, otherwise return undefined.
+    if (JSString* str = sym->description())
+        args.rval().setString(str);
+    else
+        args.rval().setUndefined();
+    return true;
+}
+
+bool
+SymbolObject::descriptionGetter(JSContext* cx, unsigned argc, Value* vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+    return CallNonGenericMethod<IsSymbol, descriptionGetter_impl>(cx, args);
+}
+
 JSObject*
 js::InitSymbolClass(JSContext* cx, HandleObject obj)
 {