Add in exception handle debugging (#373)

* Add in exception handle debugging

* Rename message for exception

Author: jonathanKingston

src/features.js

@@ -14,7 +14,8 @@ export const featureNames = [
     'fingerprintingTemporaryStorage',
     'navigatorInterface',
     'clickToLoad',
-    'elementHiding'
+    'elementHiding',
+    'exceptionHandler'
 ]
 
 // Certain features are injected into the page in Firefox

src/features/exception-handler.js

@@ -0,0 +1,19 @@
+import { postDebugMessage } from '../utils.js'
+import ContentFeature from '../content-feature.js'
+
+export default class ExceptionHandler extends ContentFeature {
+    init () {
+        // Report to the debugger panel if an uncaught exception occurs
+        function handleUncaughtException (e) {
+            postDebugMessage('jsException', {
+                documentUrl: document.location.href,
+                message: e.message,
+                filename: e.filename,
+                lineno: e.lineno,
+                colno: e.colno,
+                stack: e.error.stack
+            })
+        }
+        globalThis.addEventListener('error', handleUncaughtException)
+    }
+}