diff --git a/packages/util-crypto/src/xxhash/asHex.spec.ts b/packages/util-crypto/src/xxhash/asHex.spec.ts
index a0e7f6cc7..7ed167929 100644
--- a/packages/util-crypto/src/xxhash/asHex.spec.ts
+++ b/packages/util-crypto/src/xxhash/asHex.spec.ts
@@ -10,21 +10,23 @@ describe('xxhashAsHex', (): void => {
     await waitReady();
   });
 
-  it('returns a 64-bit value by default', (): void => {
-    expect(
-      xxhashAsHex('abc')
-    ).toEqual('0x990977adf52cbc44');
-  });
+  describe.each([false, true])('onlyJs=%p', (onlyJs): void => {
+    it('returns a 64-bit value by default', (): void => {
+      expect(
+        xxhashAsHex('abc', undefined, onlyJs)
+      ).toEqual('0x990977adf52cbc44');
+    });
 
-  it('returns a 128-bit value (as specified)', (): void => {
-    expect(
-      xxhashAsHex('abc', 128)
-    ).toEqual('0x990977adf52cbc440889329981caa9be');
-  });
+    it('returns a 128-bit value (as specified)', (): void => {
+      expect(
+        xxhashAsHex('abc', 128, onlyJs)
+      ).toEqual('0x990977adf52cbc440889329981caa9be');
+    });
 
-  it('returns a 256-bit value (as specified)', (): void => {
-    expect(
-      xxhashAsHex('abc', 256)
-    ).toEqual('0x990977adf52cbc440889329981caa9bef7da5770b2b8a05303b75d95360dd62b');
+    it('returns a 256-bit value (as specified)', (): void => {
+      expect(
+        xxhashAsHex('abc', 256, onlyJs)
+      ).toEqual('0x990977adf52cbc440889329981caa9bef7da5770b2b8a05303b75d95360dd62b');
+    });
   });
 });