improvement: [minor] add emptyMap function

Author: Christos Kotsis

db/sql.go

@@ -172,7 +172,7 @@ func (s *SQL) deleteArrayItem(k string, o interface{}) bool {
 	}
 	for ki, kn := range o.([]interface{}) {
 		if kn.(map[interface{}]interface{})[k] != nil {
-			o.([]interface{})[ki] = make(map[interface{}]interface{})
+			o.([]interface{})[ki] = emptyMap()
 			return true
 		}
 	}
@@ -317,7 +317,7 @@ func (s *SQL) upsertRecursive(k []string, o, v interface{}) error {
 		break
 	}
 
-	obj[k[0]] = make(map[interface{}]interface{})
+	obj[k[0]] = emptyMap()
 
 	if len(k) > 1 {
 		return wrapErr(s.upsertRecursive(k[1:], obj[k[0]], v))

db/storage.go

@@ -145,7 +145,7 @@ func (s *Storage) AddDoc() error {
 	} else {
 		s.AD = len(s.Data)
 	}
-	s.Data = append(s.Data, make(map[interface{}]interface{}))
+	s.Data = append(s.Data, emptyMap())
 	return s.stateReload()
 }
 

db/utils.go

@@ -38,13 +38,17 @@ func copyMap(o interface{}) (interface{}, error) {
 	return cache, nil
 }
 
+func emptyMap() map[interface{}]interface{} {
+	return make(map[interface{}]interface{})
+}
+
 func interfaceToMap(o interface{}) (map[interface{}]interface{}, error) {
 	obj, isMap := o.(map[interface{}]interface{})
 	if !isMap {
 		if o != nil {
 			return nil, wrapErr(notAMap)
 		}
-		obj = make(map[interface{}]interface{})
+		obj = emptyMap()
 	}
 	return obj, nil
 }