From 053a7dfed1bbd4200d09f886b170b9ce6d2e4099 Mon Sep 17 00:00:00 2001
From: "Manu Mtz.-Almeida" <manu.mtza@gmail.com>
Date: Tue, 6 Aug 2019 10:09:13 +0200
Subject: [PATCH] feat(): emit warning when emitting event while disconnected

---
 src/runtime/event-emitter.ts | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/runtime/event-emitter.ts b/src/runtime/event-emitter.ts
index b3de2b82925..4a986ec56fb 100644
--- a/src/runtime/event-emitter.ts
+++ b/src/runtime/event-emitter.ts
@@ -5,15 +5,20 @@ import { getElement, win } from '@platform';
 
 
 export const createEvent = (ref: d.RuntimeRef, name: string, flags: number) => {
-  const elm = getElement(ref);
+  const elm = getElement(ref) as HTMLElement;
   return {
-    emit: (detail: any) => elm.dispatchEvent(
-      new (BUILD.hydrateServerSide ? (win as any).CustomEvent : CustomEvent)(name, {
-        bubbles: !!(flags & EVENT_FLAGS.Bubbles),
-        composed: !!(flags & EVENT_FLAGS.Composed),
-        cancelable: !!(flags & EVENT_FLAGS.Cancellable),
-        detail
-      })
-    )
+    emit: (detail: any) => {
+      if (BUILD.isDev && !elm.isConnected) {
+        console.warn(`The "${name}" event was emitted, but the dispatcher node is not longer connected to the dom.`);
+      }
+      return elm.dispatchEvent(
+        new (BUILD.hydrateServerSide ? (win as any).CustomEvent : CustomEvent)(name, {
+          bubbles: !!(flags & EVENT_FLAGS.Bubbles),
+          composed: !!(flags & EVENT_FLAGS.Composed),
+          cancelable: !!(flags & EVENT_FLAGS.Cancellable),
+          detail
+        })
+      );
+    }
   };
 };