Added support for creating objects in golang function callbacks.

object.go

@@ -19,6 +19,12 @@ type Object struct {
 	*Value
 }
 
+// Instantiate a new blank object without any properties.
+// Add properties on the object using Set.
+func NewObject(ctx *Context) *Object {
+	return &Object{&Value{C.NewObject(ctx.iso.ptr), ctx}}
+}
+
 // Set will set a property on the Object to a given value.
 // Supports all value types, eg: Object, Array, Date, Set, Map etc
 // If the value passed is a Go supported primitive (string, int32, uint32, int64, uint64, float64, big.Int)

object_test.go

@@ -5,7 +5,9 @@
 package v8go_test
 
 import (
+	"errors"
 	"fmt"
+	"log"
 	"testing"
 
 	"rogchap.com/v8go"
@@ -114,3 +116,97 @@ func ExampleObject_global() {
 	// Output:
 	// foo
 }
+
+type objectTester struct{}
+
+func (a *objectTester) GetCreateObjectFunctionCallback() v8go.FunctionCallback {
+	return func(info *v8go.FunctionCallbackInfo) *v8go.Value {
+		iso, err := info.Context().Isolate()
+		if err != nil {
+			log.Fatalf("Could not get isolate from context: %v\n", err)
+		}
+		args := info.Args()
+		if len(args) != 2 {
+			return iso.ThrowException("Function CreateObject expects 2 parameters")
+		}
+		if !args[0].IsInt32() || !args[1].IsInt32() {
+			return iso.ThrowException("Function CreateObject expects 2 Int32 parameters")
+		}
+		read := args[0].Int32()
+		written := args[1].Int32()
+		obj := v8go.NewObject(info.Context()) // create object
+		obj.Set("read", read)                 // set some properties
+		obj.Set("written", written)
+		return obj.Value
+	}
+}
+
+func injectObjectTester(ctx *v8go.Context, funcName string, funcCb v8go.FunctionCallback) error {
+	if ctx == nil {
+		return errors.New("ctx is required")
+	}
+
+	iso, err := ctx.Isolate()
+	if err != nil {
+		return fmt.Errorf("ctx.Isolate: %v", err)
+	}
+
+	con, err := v8go.NewObjectTemplate(iso)
+	if err != nil {
+		return fmt.Errorf("NewObjectTemplate: %v", err)
+	}
+
+	funcTempl, err := v8go.NewFunctionTemplate(iso, funcCb)
+	if err != nil {
+		return fmt.Errorf("NewFunctionTemplate: %v", err)
+	}
+
+	if err := con.Set(funcName, funcTempl, v8go.ReadOnly); err != nil {
+		return fmt.Errorf("ObjectTemplate.Set: %v", err)
+	}
+
+	nativeObj, err := con.NewInstance(ctx)
+	if err != nil {
+		return fmt.Errorf("ObjectTemplate.NewInstance: %v", err)
+	}
+
+	global := ctx.Global()
+
+	if err := global.Set("native", nativeObj); err != nil {
+		return fmt.Errorf("global.Set: %v", err)
+	}
+
+	return nil
+}
+
+// Test that golang can create an object with "read", "written" int32 properties and pass that back to JS.
+func TestObjectCreate(t *testing.T) {
+	t.Parallel()
+	iso, _ := v8go.NewIsolate()
+	ctx, _ := v8go.NewContext(iso)
+	c := &objectTester{}
+
+	if err := injectObjectTester(ctx, "createObject", c.GetCreateObjectFunctionCallback()); err != nil {
+		t.Error(err)
+	}
+
+	js := `
+		obj = native.createObject(123, 456);
+		obj.read + obj.written;
+	`
+
+	val, err := ctx.RunScript(js, "")
+	if err != nil {
+		t.Errorf("Got error from script: %v", err)
+	}
+	if val == nil {
+		t.Errorf("Got nil value from script")
+	}
+	if !val.IsInt32() {
+		t.Errorf("Expected int32 value from script")
+	}
+	fmt.Printf("Script return value: %d\n", val.Int32())
+	if val.Int32() != 123+456 {
+		t.Errorf("Got wrong return value from script: %d", val.Int32())
+	}
+}

v8go.cc

@@ -1024,6 +1024,19 @@ int ValueIsModuleNamespaceObject(ValuePtr ptr) {
   LOCAL_VALUE(ptr)        \
   Local<Object> obj = value.As<Object>()
 
+ValuePtr NewObject(IsolatePtr iso_ptr) {
+  ISOLATE_SCOPE_INTERNAL_CONTEXT(iso_ptr);
+  Local<Context> c = ctx->ptr.Get(iso);
+  Local<Object> obj = Object::New(iso);
+
+  m_value* val = new m_value;
+  val->iso = iso;
+  val->ctx = ctx;
+  val->ptr = Persistent<Value, CopyablePersistentTraits<Value>>(iso, obj);
+
+  return tracked_value(ctx, val);
+}
+
 void ObjectSet(ValuePtr ptr, const char* key, ValuePtr val_ptr) {
   LOCAL_OBJECT(ptr);
   Local<String> key_val =

v8go.h

@@ -162,6 +162,7 @@ int ValueIsProxy(ValuePtr ptr);
 int ValueIsWasmModuleObject(ValuePtr ptr);
 int ValueIsModuleNamespaceObject(ValuePtr ptr);
 
+extern ValuePtr NewObject(IsolatePtr iso_ptr);
 extern void ObjectSet(ValuePtr ptr, const char* key, ValuePtr val_ptr);
 extern void ObjectSetIdx(ValuePtr ptr, uint32_t idx, ValuePtr val_ptr);
 extern RtnValue ObjectGet(ValuePtr ptr, const char* key);