1 files changed, 29 insertions, 0 deletions
diff --git a/packages/taler-wallet-core/src/util/invariants.ts b/packages/taler-wallet-core/src/util/invariants.ts
new file mode 100644
index 000000000..fa381d333
--- /dev/null
+++ b/packages/taler-wallet-core/src/util/invariants.ts
@@ -0,0 +1,29 @@
+/*
+ This file is part of GNU Taler
+ (C) 2020 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+/**
+ * Helpers for invariants.
+ */
+
+export function checkDbInvariant(b: boolean, m?: string): asserts b {
+  if (!b) {
+    if (m) {
+      throw Error(`BUG: database invariant failed (${m})`);
+    } else {
+      throw Error("BUG: database invariant failed");
+    }
+  }
+}