Add default implementation for Object.create(prototype) (facebook#47946)

Summary:

Object creation with custom prototype can currently be done, but it is
unnecessarily convoluted. Users have to call into the global object to
get the `Object.create` function, then call it with the custom
prototype.

This diff adds a JSI API for Object.create(prototype) to make it easy
for users.

Changelog: [Internal]

Differential Revision: D66485209

packages/react-native/ReactCommon/jsi/jsi/decorator.h

@@ -232,6 +232,10 @@ class RuntimeDecorator : public Base, private jsi::Instrumentation {
     return plain_.utf16(sym);
   }
 
+  Object createObjectWithPrototype(const Value& prototype) override {
+    return plain_.createObjectWithPrototype(prototype);
+  }
+
   Object createObject() override {
     return plain_.createObject();
   };
@@ -695,6 +699,11 @@ class WithRuntimeDecorator : public RuntimeDecorator<Plain, Base> {
     return RD::createValueFromJsonUtf8(json, length);
   };
 
+  Object createObjectWithPrototype(const Value& prototype) override {
+    Around around{with_};
+    return RD::createObjectWithPrototype(prototype);
+  }
+
   Object createObject() override {
     Around around{with_};
     return RD::createObject();

packages/react-native/ReactCommon/jsi/jsi/jsi.cpp

@@ -258,6 +258,16 @@ std::u16string Runtime::utf16(const String& str) {
   return convertUTF8ToUTF16(utf8Str);
 }
 
+Object Runtime::createObjectWithPrototype(const Value& prototype) {
+  if (!prototype.isObject() && !prototype.isNull()) {
+    throw JSError(*this, "Object prototype argument must be an Object or null");
+  }
+  auto createFn = global()
+                      .getPropertyAsObject(*this, "Object")
+                      .getPropertyAsFunction(*this, "create");
+  return createFn.call(*this, prototype).asObject(*this);
+}
+
 Pointer& Pointer::operator=(Pointer&& other) noexcept {
   if (ptr_) {
     ptr_->invalidate();

packages/react-native/ReactCommon/jsi/jsi/jsi.h

@@ -333,6 +333,9 @@ class JSI_EXPORT Runtime {
   virtual std::shared_ptr<HostObject> getHostObject(const jsi::Object&) = 0;
   virtual HostFunctionType& getHostFunction(const jsi::Function&) = 0;
 
+  // Creates a new Object with the custom prototype
+  virtual Object createObjectWithPrototype(const Value& prototype);
+
   virtual bool hasNativeState(const jsi::Object&) = 0;
   virtual std::shared_ptr<NativeState> getNativeState(const jsi::Object&) = 0;
   virtual void setNativeState(
@@ -688,6 +691,11 @@ class JSI_EXPORT Object : public Pointer {
     return runtime.createObject(ho);
   }
 
+  /// Creates a new Object with the custom prototype
+  static Object create(Runtime& runtime, const Value& prototype) {
+    return runtime.createObjectWithPrototype(prototype);
+  }
+
   /// \return whether this and \c obj are the same JSObject or not.
   static bool strictEquals(Runtime& runtime, const Object& a, const Object& b) {
     return runtime.strictEquals(a, b);

packages/react-native/ReactCommon/jsi/jsi/test/testlib.cpp

@@ -1635,6 +1635,34 @@ TEST_P(JSITest, UTF16Test) {
   EXPECT_EQ(str.utf16(rd), u"\uFFFD\u007A");
 }
 
+TEST_P(JSITest, ObjectCreateWithPrototype) {
+  // This Runtime Decorator is used to test the default implementation of
+  // Object.create(prototype)
+  class RD : public RuntimeDecorator<Runtime, Runtime> {
+   public:
+    RD(Runtime& rt) : RuntimeDecorator(rt) {}
+
+    Object createObjectWithPrototype(const Value& prototype) override {
+      return Runtime::createObjectWithPrototype(prototype);
+    }
+  };
+
+  RD rd = RD(rt);
+  Object prototypeObj(rd);
+  prototypeObj.setProperty(rd, "someProperty", 123);
+  Value prototype(rd, prototypeObj);
+
+  Object child = Object::create(rd, prototype);
+  EXPECT_EQ(child.getProperty(rd, "someProperty").getNumber(), 123);
+
+  // Tests null value as prototype
+  child = Object::create(rd, Value::null());
+  EXPECT_TRUE(child.getProperty(rd, "__proto__").isUndefined());
+
+  // Throw when prototype is neither an Object nor null
+  EXPECT_THROW(Object::create(rd, Value(1)), JSError);
+}
+
 INSTANTIATE_TEST_CASE_P(
     Runtimes,
     JSITest,