From 798800c65347eab3b3ee74d3b7bd08ffc46d015e Mon Sep 17 00:00:00 2001
From: catch <catch@35733.no-reply.drupal.org>
Date: Mon, 11 Jul 2022 23:41:11 +0900
Subject: [PATCH] Issue #3294720 by abramm: The attachBehaviors() for document
 is only called after Big Pipe chunks are processed

---
 core/modules/big_pipe/js/big_pipe.es6.js | 5 +++++
 core/modules/big_pipe/js/big_pipe.js     | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/core/modules/big_pipe/js/big_pipe.es6.js b/core/modules/big_pipe/js/big_pipe.es6.js
index 0792a793ee1..097a036472d 100644
--- a/core/modules/big_pipe/js/big_pipe.es6.js
+++ b/core/modules/big_pipe/js/big_pipe.es6.js
@@ -93,6 +93,11 @@
       return false;
     }
 
+    // Attach Drupal behaviors early, if possible.
+    once('big-pipe-early-behaviors', 'body', context).forEach((el) => {
+      Drupal.attachBehaviors(el);
+    });
+
     once(
       'big-pipe',
       'script[data-big-pipe-replacement-for-placeholder-with-id]',
diff --git a/core/modules/big_pipe/js/big_pipe.js b/core/modules/big_pipe/js/big_pipe.js
index edcf98f0a76..e9e8497bf09 100644
--- a/core/modules/big_pipe/js/big_pipe.js
+++ b/core/modules/big_pipe/js/big_pipe.js
@@ -47,6 +47,9 @@
       return false;
     }
 
+    once('big-pipe-early-behaviors', 'body', context).forEach(el => {
+      Drupal.attachBehaviors(el);
+    });
     once('big-pipe', 'script[data-big-pipe-replacement-for-placeholder-with-id]', context).forEach(bigPipeProcessPlaceholderReplacement);
 
     if (context.querySelector('script[data-big-pipe-event="stop"]')) {