fix(runtime): don't crash when window is deleted (#13392)

This commit fixes an error when user deletes "window" global JS
variable. Instead of relying on "window" or "globalThis" to dispatch
"load" and "unload" events, we are default to global scope of the
worker.

1 files changed, 5 insertions, 1 deletions

diff --git a/ext/web/02_event.js b/ext/web/02_event.js
index f9a69c625..7ba5afa27 100644
--- a/ext/web/02_event.js
+++ b/ext/web/02_event.js
@@ -970,7 +970,11 @@
       webidl.requiredArguments(arguments.length, 1, {
         prefix: "Failed to execute 'dispatchEvent' on 'EventTarget'",
       });
-      const self = this ?? globalThis;
+      // If `this` is not present, then fallback to global scope. We don't use
+      // `globalThis` directly here, because it could be deleted by user.
+      // Instead use saved reference to global scope when the script was
+      // executed.
+      const self = this ?? window;
 
       const { listeners } = self[eventTargetData];
       if (!(event.type in listeners)) {