From 5545d160572d8a27f56d61321e4358ac861fe807 Mon Sep 17 00:00:00 2001
From: Mattias Andersson <mattias800@gmail.com>
Date: Wed, 4 Sep 2024 13:36:17 +0200
Subject: [PATCH] Add invariant method (#780)

- Add invariant method to core.
---
 packages/core/src/index.ts           | 1 +
 packages/core/src/utils/Invariant.ts | 8 ++++++++
 2 files changed, 9 insertions(+)
 create mode 100644 packages/core/src/utils/Invariant.ts

diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 985266eb7..2165e9be0 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -52,3 +52,4 @@ export * from "./utils/TruthyKeysAsList";
 export * from "./utils/PropsForwarder";
 export * from "./utils/parsers/NumberParser";
 export { booleanOrNumberToNumber } from "./utils/BooleanOrNumberToNumber";
+export * from "./utils/Invariant";
diff --git a/packages/core/src/utils/Invariant.ts b/packages/core/src/utils/Invariant.ts
new file mode 100644
index 000000000..d53caf37e
--- /dev/null
+++ b/packages/core/src/utils/Invariant.ts
@@ -0,0 +1,8 @@
+export function invariant<T>(
+  val: T | null | undefined,
+  message: string
+): asserts val is T {
+  if (val == null) {
+    throw new Error("Invariant error: " + message);
+  }
+}