chore(dataservices): enhance ReadAll() so it takes predicates for filtering results BE-12016 (#866)

api/dataservices/base_tx.go

@@ -34,13 +34,32 @@ func (service BaseDataServiceTx[T, I]) Exists(ID I) (bool, error) {
 	return service.Tx.KeyExists(service.Bucket, identifier)
 }
 
-func (service BaseDataServiceTx[T, I]) ReadAll() ([]T, error) {
+// ReadAll retrieves all the elements that satisfy all the provided predicates.
+func (service BaseDataServiceTx[T, I]) ReadAll(predicates ...func(T) bool) ([]T, error) {
 	var collection = make([]T, 0)
 
+	if len(predicates) == 0 {
+		return collection, service.Tx.GetAll(
+			service.Bucket,
+			new(T),
+			AppendFn(&collection),
+		)
+	}
+
+	filterFn := func(element T) bool {
+		for _, p := range predicates {
+			if !p(element) {
+				return false
+			}
+		}
+
+		return true
+	}
+
 	return collection, service.Tx.GetAll(
 		service.Bucket,
 		new(T),
-		AppendFn(&collection),
+		FilterFn(&collection, filterFn),
 	)
 }