fix: map export (#467)

When exporting a map check for values which are otto.Value and process
them. This is a one level export and no additional traversal is done.

Fixes #252

issue_test.go

@@ -3,6 +3,7 @@ package otto
 import (
 	"database/sql"
 	"database/sql/driver"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"testing"
@@ -1074,3 +1075,33 @@ func Test_issue317(t *testing.T) {
 		})
 	}
 }
+
+func Test_issue252(t *testing.T) {
+	in := map[string]interface{}{
+		"attr": []interface{}{"string"},
+	}
+	expected := map[string]interface{}{
+		"attr": []string{"changed"},
+	}
+
+	vm := New()
+	err := vm.Set("In", in)
+	require.NoError(t, err)
+
+	result, err := vm.Run(`(function fn() {
+		var tmp = In;
+		tmp.attr = ["changed"];
+		return tmp;
+	})()`)
+	require.NoError(t, err)
+
+	actual, err := result.Export()
+	require.NoError(t, err)
+	require.Equal(t, expected, actual)
+
+	expBs, err := json.Marshal(expected)
+	require.NoError(t, err)
+	actBs, err := json.Marshal(actual)
+	require.NoError(t, err)
+	require.Equal(t, expBs, actBs)
+}

value.go

@@ -645,6 +645,13 @@ func (self Value) export() interface{} {
 		case *_goStructObject:
 			return value.value.Interface()
 		case *_goMapObject:
+			iter := value.value.MapRange()
+			for iter.Next() {
+				v := iter.Value()
+				if ov, ok := v.Interface().(Value); ok {
+					value.value.SetMapIndex(iter.Key(), reflect.ValueOf(ov.export()))
+				}
+			}
 			return value.value.Interface()
 		case *_goArrayObject:
 			return value.value.Interface()