2 files changed, 29 insertions, 10 deletions
diff --git a/cli/rt/11_workers.js b/cli/rt/11_workers.js
index 36a2fd61b..62210dfae 100644
--- a/cli/rt/11_workers.js
+++ b/cli/rt/11_workers.js
@@ -4,6 +4,7 @@
   const core = window.Deno.core;
   const { Window } = window.__bootstrap.globalInterfaces;
   const { log } = window.__bootstrap.util;
+  const { defineEventHandler } = window.__bootstrap.webUtil;
 
   function createWorker(
     specifier,
@@ -87,9 +88,6 @@
           cancelable: false,
           data,
         });
-        if (this.onmessageerror) {
-          this.onmessageerror(msgErrorEvent);
-        }
         return;
       }
 
@@ -98,10 +96,6 @@
         data,
       });
 
-      if (this.onmessage) {
-        this.onmessage(msgEvent);
-      }
-
       this.dispatchEvent(msgEvent);
     };
 
@@ -116,9 +110,6 @@
       });
 
       let handled = false;
-      if (this.onerror) {
-        this.onerror(event);
-      }
 
       this.dispatchEvent(event);
       if (event.defaultPrevented) {
@@ -205,6 +196,10 @@
     }
   }
 
+  defineEventHandler(Worker.prototype, "error");
+  defineEventHandler(Worker.prototype, "message");
+  defineEventHandler(Worker.prototype, "messageerror");
+
   window.__bootstrap.worker = {
     Worker,
   };
diff --git a/cli/tests/workers_test.ts b/cli/tests/workers_test.ts
index 31dc72deb..7cff6848b 100644
--- a/cli/tests/workers_test.ts
+++ b/cli/tests/workers_test.ts
@@ -334,3 +334,27 @@ Deno.test({
     w.terminate();
   },
 });
+
+Deno.test({
+  name: "Worker event handler order",
+  fn: async function (): Promise<void> {
+    const promise = createResolvable();
+    const w = new Worker(
+      new URL("subdir/test_worker.ts", import.meta.url).href,
+      { type: "module", name: "tsWorker" },
+    );
+    const arr: number[] = [];
+    w.addEventListener("message", () => arr.push(1));
+    w.onmessage = (e): void => {
+      arr.push(2);
+    };
+    w.addEventListener("message", () => arr.push(3));
+    w.addEventListener("message", () => {
+      assertEquals(arr, [1, 2, 3]);
+      promise.resolve();
+    });
+    w.postMessage("Hello World");
+    await promise;
+    w.terminate();
+  },
+});