diff --git a/utils/jsffi/prelude.mjs b/utils/jsffi/prelude.mjs
index c9cd6a447d482d8fec202099df5ba947f809d792..b32a843ce27e6929836e04d122cd76ce8a21f69f 100644
--- a/utils/jsffi/prelude.mjs
+++ b/utils/jsffi/prelude.mjs
@@ -58,9 +58,9 @@ const setImmediate = await (async () => {
   }
 
   // deno
-  try {
+  if (globalThis.Deno) {
     return (await import("node:timers")).setImmediate;
-  } catch {}
+  }
 
   // https://developer.mozilla.org/en-US/docs/Web/API/Scheduler/postTask
   if (globalThis.scheduler) {