From c891bd09e3de435e9c6113d248bd43dcfd256372 Mon Sep 17 00:00:00 2001
From: Sam Seay <samueljseay@gmail.com>
Date: Wed, 18 Sep 2024 10:13:47 +0800
Subject: [PATCH] Check if button element exists when triggering added_to_cart
 (#51449)

---
 .../changelog/51449-dev-harden-added-to-cart  |  4 +++
 .../client/legacy/js/frontend/add-to-cart.js  | 30 ++++++++++++-------
 2 files changed, 23 insertions(+), 11 deletions(-)
 create mode 100644 plugins/woocommerce/changelog/51449-dev-harden-added-to-cart

diff --git a/plugins/woocommerce/changelog/51449-dev-harden-added-to-cart b/plugins/woocommerce/changelog/51449-dev-harden-added-to-cart
new file mode 100644
index 00000000000..99351de4130
--- /dev/null
+++ b/plugins/woocommerce/changelog/51449-dev-harden-added-to-cart
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fix
+
+Fix bug where manually triggering `added_to_cart` event without a button element caused an Exception.
\ No newline at end of file
diff --git a/plugins/woocommerce/client/legacy/js/frontend/add-to-cart.js b/plugins/woocommerce/client/legacy/js/frontend/add-to-cart.js
index a99e4394750..dd2e0872c86 100644
--- a/plugins/woocommerce/client/legacy/js/frontend/add-to-cart.js
+++ b/plugins/woocommerce/client/legacy/js/frontend/add-to-cart.js
@@ -173,6 +173,8 @@ jQuery( function( $ ) {
 	 * Update cart page elements after add to cart events.
 	 */
 	AddToCartHandler.prototype.updateButton = function( e, fragments, cart_hash, $button ) {
+		// Some themes and plugins manually trigger added_to_cart without passing a button element, which in turn calls this function.
+		// If there is no button we don't want to crash.
 		$button = typeof $button === 'undefined' ? false : $button;
 
 		if ( $button ) {
@@ -222,19 +224,25 @@ jQuery( function( $ ) {
 	 * Update cart live region message after add/remove cart events.
 	 */
 	AddToCartHandler.prototype.alertCartUpdated = function( e, fragments, cart_hash, $button ) {
-		var message = $button.data( 'success_message' );
+		// Some themes and plugins manually trigger added_to_cart without passing a button element, which in turn calls this function.
+		// If there is no button we don't want to crash.
+		$button = typeof $button === 'undefined' ? false : $button;
 
-		if ( !message ) {
-			return;
-		}
+		if ( $button ) {
+			var message = $button.data( 'success_message' );
+
+			if ( !message ) {
+				return;
+			}
 		
-		// If the response after adding/removing an item to/from the cart is really fast,
-		// screen readers may not have time to identify the changes in the live region element. 
-		// So, we add a delay to ensure an interval between messages.
-		e.data.addToCartHandler.$liveRegion
-			.delay(1000)
-			.text( message )
-			.attr( 'aria-relevant', 'all' );
+			// If the response after adding/removing an item to/from the cart is really fast,
+			// screen readers may not have time to identify the changes in the live region element. 
+			// So, we add a delay to ensure an interval between messages.
+			e.data.addToCartHandler.$liveRegion
+				.delay(1000)
+				.text( message )
+				.attr( 'aria-relevant', 'all' );
+		}
 	};
 
 	/**