make it generic

structs/structs.go

@@ -43,14 +43,15 @@ func Walk(s interface{}, callback CallbackFunc) {
 // - input: the original struct.
 // - includeFields: list of fields to include (if empty, includes all).
 // - excludeFields: list of fields to exclude (processed after include).
-func FilterStruct(input interface{}, includeFields, excludeFields []string) (interface{}, error) {
+func FilterStruct[T any](input T, includeFields, excludeFields []string) (T, error) {
+	var zeroValue T
 	val := reflect.ValueOf(input)
 	if val.Kind() == reflect.Ptr {
 		val = val.Elem()
 	}
 
 	if val.Kind() != reflect.Struct {
-		return nil, errors.New("input must be a struct")
+		return zeroValue, errors.New("input must be a struct")
 	}
 
 	includeMap := make(map[string]bool)
@@ -76,13 +77,13 @@ func FilterStruct(input interface{}, includeFields, excludeFields []string) (int
 		}
 	}
 
-	return filteredStruct.Interface(), nil
+	return filteredStruct.Interface().(T), nil
 }
 
 // GetStructFields returns all the top-level field names from the given struct.
 // - input: the original struct.
 // Returns a slice of field names or an error if the input is not a struct.
-func GetStructFields(input interface{}) ([]string, error) {
+func GetStructFields[T any](input T) ([]string, error) {
 	val := reflect.ValueOf(input)
 	if val.Kind() == reflect.Ptr {
 		val = val.Elem()