2 files changed, 40 insertions, 2 deletions

diff --git a/runtime/web_worker.rs b/runtime/web_worker.rs
index 30869ff41..73d351c9c 100644
--- a/runtime/web_worker.rs
+++ b/runtime/web_worker.rs
@@ -325,7 +325,28 @@ impl WebWorker {
     module_specifier: &ModuleSpecifier,
   ) -> Result<(), AnyError> {
     let id = self.js_runtime.load_module(module_specifier, None).await?;
-    self.js_runtime.mod_evaluate(id).await
+
+    let mut receiver = self.js_runtime.mod_evaluate(id);
+    tokio::select! {
+      maybe_result = receiver.next() => {
+        debug!("received worker module evaluate {:#?}", maybe_result);
+        // If `None` is returned it means that runtime was destroyed before
+        // evaluation was complete. This can happen in Web Worker when `self.close()`
+        // is called at top level.
+        let result = maybe_result.unwrap_or(Ok(()));
+        return result;
+      }
+
+      event_loop_result = self.run_event_loop() => {
+        if self.has_been_terminated() {
+          return Ok(());
+        }
+        event_loop_result?;
+        let maybe_result = receiver.next().await;
+        let result = maybe_result.unwrap_or(Ok(()));
+        return result;
+      }
+    }
   }
 
   /// Returns a way to communicate with the Worker from other threads.
@@ -384,6 +405,8 @@ impl WebWorker {
       let msg = String::from_utf8(msg.to_vec()).unwrap();
       let script = format!("workerMessageRecvCallback({})", msg);
 
+      // TODO(bartlomieju): set proper script name like "deno:runtime/web_worker.js"
+      // so it's dimmed in stack trace instead of using "__anonymous__"
       if let Err(e) = self.execute(&script) {
         // If execution was terminated during message callback then
         // just ignore it
diff --git a/runtime/worker.rs b/runtime/worker.rs
index 97466fadb..e63fdbe18 100644
--- a/runtime/worker.rs
+++ b/runtime/worker.rs
@@ -10,6 +10,7 @@ use crate::permissions::Permissions;
 use deno_core::error::AnyError;
 use deno_core::futures::future::poll_fn;
 use deno_core::futures::future::FutureExt;
+use deno_core::futures::stream::StreamExt;
 use deno_core::serde_json;
 use deno_core::serde_json::json;
 use deno_core::url::Url;
@@ -221,7 +222,21 @@ impl MainWorker {
   ) -> Result<(), AnyError> {
     let id = self.preload_module(module_specifier).await?;
     self.wait_for_inspector_session();
-    self.js_runtime.mod_evaluate(id).await
+    let mut receiver = self.js_runtime.mod_evaluate(id);
+    tokio::select! {
+      maybe_result = receiver.next() => {
+        debug!("received module evaluate {:#?}", maybe_result);
+        let result = maybe_result.expect("Module evaluation result not provided.");
+        return result;
+      }
+
+      event_loop_result = self.run_event_loop() => {
+        event_loop_result?;
+        let maybe_result = receiver.next().await;
+        let result = maybe_result.expect("Module evaluation result not provided.");
+        return result;
+      }
+    }
   }
 
   fn wait_for_inspector_session(&mut self) {