1 files changed, 9 insertions, 0 deletions
diff --git a/js/util.ts b/js/util.ts
index f65477ee5..c4bada589 100644
--- a/js/util.ts
+++ b/js/util.ts
@@ -85,6 +85,7 @@ export function unreachable(): never {
   throw new Error("Code not reachable");
 }
 
+// @internal
 export function hexdump(u8: Uint8Array): string {
   return Array.prototype.map
     .call(u8, (x: number) => {
@@ -92,3 +93,11 @@ export function hexdump(u8: Uint8Array): string {
     })
     .join(" ");
 }
+
+// @internal
+export function containsOnlyASCII(str: string): boolean {
+  if (typeof str !== "string") {
+    return false;
+  }
+  return /^[\x00-\x7F]*$/.test(str);
+}