idb wip

1 files changed, 18 insertions, 0 deletions

diff --git a/packages/idb-bridge/src/util/enforceRange.ts b/packages/idb-bridge/src/util/enforceRange.ts
new file mode 100644
index 000000000..0cf3b6c85
--- /dev/null
+++ b/packages/idb-bridge/src/util/enforceRange.ts
@@ -0,0 +1,18 @@
+// https://heycam.github.io/webidl/#EnforceRange
+
+const enforceRange = (
+    num: number,
+    type: "MAX_SAFE_INTEGER" | "unsigned long",
+) => {
+    const min = 0;
+    const max = type === "unsigned long" ? 4294967295 : 9007199254740991;
+
+    if (isNaN(num) || num < min || num > max) {
+        throw new TypeError();
+    }
+    if (num >= 0) {
+        return Math.floor(num);
+    }
+};
+
+export default enforceRange;