From 570f055980d4cec23483d2fdb71cd724c21db692 Mon Sep 17 00:00:00 2001
From: Brett Ausmeier <brett@decodedev.co.za>
Date: Tue, 27 May 2025 19:47:19 +0200
Subject: [PATCH] Fix skipping of event handlers

Event handlers registered after a `once` handler were being silently
skipped, causing unpredictable behaviour in tour interactions. This
occurred because modifying an array during iteration is unsafe.

Making a copy of the bindings array before iteration prevents these
handers from being skipped.
---
 shepherd.js/src/evented.ts | 2 +-
 test/unit/evented.spec.js  | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/shepherd.js/src/evented.ts b/shepherd.js/src/evented.ts
index 95f55500f..c539e1912 100644
--- a/shepherd.js/src/evented.ts
+++ b/shepherd.js/src/evented.ts
@@ -77,7 +77,7 @@ export class Evented {
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   trigger(event: string, ...args: any[]) {
     if (!isUndefined(this.bindings) && this.bindings[event]) {
-      this.bindings[event]?.forEach((binding, index) => {
+      this.bindings[event]?.slice().forEach((binding, index) => {
         const { ctx, handler, once } = binding;
 
         const context = ctx || this;
diff --git a/test/unit/evented.spec.js b/test/unit/evented.spec.js
index 45b5ce108..0949603b3 100644
--- a/test/unit/evented.spec.js
+++ b/test/unit/evented.spec.js
@@ -38,6 +38,14 @@ describe('Evented', () => {
         step: { id: 'test', text: 'A step' }
       });
     });
+
+    it('does not skip event bindings after removing an event binding', () => {
+      testEvent.once('testOn', () => true);
+      const handlerSpy = jest.fn();
+      testEvent.on('testOn', handlerSpy);
+      testEvent.trigger('testOn');
+      expect(handlerSpy).toHaveBeenCalled();
+    });
   });
 
   describe('off()', () => {