diff --git a/lighthouse-core/gather/driver.js b/lighthouse-core/gather/driver.js
index 33e68f903173..693d4b1c925b 100644
--- a/lighthouse-core/gather/driver.js
+++ b/lighthouse-core/gather/driver.js
@@ -73,11 +73,11 @@ class Driver {
       if (this._networkStatusMonitor) {
         this._networkStatusMonitor.dispatch(event);
       }
-      if (event.params) {
-        this._eventEmitter.emit(event.method, event.params);
-      } else {
-        this._eventEmitter.emit(event.method);
-      }
+
+      // @ts-ignore TODO(bckenny): tsc can't type event.params correctly yet,
+      // typing as property of union instead of narrowing from union of
+      // properties. See https://github.com/Microsoft/TypeScript/pull/22348.
+      this._eventEmitter.emit(event.method, event.params);
     });
   }