1 files changed, 6 insertions, 3 deletions
diff --git a/runtime/js/30_os.js b/runtime/js/30_os.js
index 1d700b561..5a3c990b0 100644
--- a/runtime/js/30_os.js
+++ b/runtime/js/30_os.js
@@ -24,9 +24,12 @@
   }
 
   function exit(code = 0) {
-    // Invokes the `unload` hooks before exiting
-    // ref: https://github.com/denoland/deno/issues/3603
-    window.dispatchEvent(new Event("unload"));
+    // Dispatches `unload` only when it's not dispatched yet.
+    if (!window[Symbol.for("isUnloadDispatched")]) {
+      // Invokes the `unload` hooks before exiting
+      // ref: https://github.com/denoland/deno/issues/3603
+      window.dispatchEvent(new Event("unload"));
+    }
     core.jsonOpSync("op_exit", { code });
     throw new Error("Code not reachable");
   }