From e1f2e0656b15b7d1de564295a5afdf6feeae6d7a Mon Sep 17 00:00:00 2001
From: Gerrit Riessen <gerrit@openmindmap.org>
Date: Fri, 15 Dec 2023 10:54:11 +0100
Subject: [PATCH] Client Events: fix off-in-on pattern emulating once

This fixes an issue when RED.events.off(..) is called in a RED.events.on(..) callback:

```
let cb = () => {
  RED.events.off("event-name", cb)
  ....
}
RED.events.on("event-name", cb)
```

This pattern emulates a once(..), i.e., execute a callback once-only for an event.

Discussed in [Forum](https://discourse.nodered.org/t/event-offing-an-on-event-to-perform-only-once/83726)
---
 .../node_modules/@node-red/editor-client/src/js/events.js  | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/packages/node_modules/@node-red/editor-client/src/js/events.js b/packages/node_modules/@node-red/editor-client/src/js/events.js
index bd2abd8d0..943854393 100644
--- a/packages/node_modules/@node-red/editor-client/src/js/events.js
+++ b/packages/node_modules/@node-red/editor-client/src/js/events.js
@@ -39,15 +39,16 @@
              console.warn(evt,args);
          }
          if (handlers[evt]) {
-             for (var i=0;i<handlers[evt].length;i++) {
+             let cpyHandlers = [...handlers[evt]];
+          
+             for (var i=0;i<cpyHandlers.length;i++) {
                  try {
-                     handlers[evt][i].apply(null, args);
+                     cpyHandlers[i].apply(null, args);
                  } catch(err) {
                      console.warn("RED.events.emit error: ["+evt+"] "+(err.toString()));
                      console.warn(err);
                  }
              }
-
          }
      }
      return {