From 0d1f555948bf41e65e54daa234701dbb4358fd95 Mon Sep 17 00:00:00 2001
From: Jan Klimke <jan.klimke@hpi.de>
Date: Thu, 5 Aug 2021 14:24:03 +0200
Subject: [PATCH 1/2] removed invalid .then call using lib.promiseError which
 does not exist anymore since 2016

---
 src/lib/index.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/lib/index.js b/src/lib/index.js
index d838ddfc948..5d97f2cfc89 100644
--- a/src/lib/index.js
+++ b/src/lib/index.js
@@ -455,8 +455,7 @@ lib.syncOrAsync = function(sequence, arg, finalStep) {
         ret = fni(arg);
 
         if(ret && ret.then) {
-            return ret.then(continueAsync)
-                .then(undefined, lib.promiseError);
+            return ret.then(continueAsync);
         }
     }
 

From 1fa7b3407d24779387f3fb258264e7f267f102d0 Mon Sep 17 00:00:00 2001
From: Jan Klimke <jan.klimke@hpi.de>
Date: Thu, 5 Aug 2021 15:16:08 +0200
Subject: [PATCH 2/2] added draftlog 5878_fix.md

---
 draftlogs/5878_fix.md | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 draftlogs/5878_fix.md

diff --git a/draftlogs/5878_fix.md b/draftlogs/5878_fix.md
new file mode 100644
index 00000000000..cd7b8f0ec6f
--- /dev/null
+++ b/draftlogs/5878_fix.md
@@ -0,0 +1,2 @@
+ - Fix invalid call to `lib.promiseError` in lib.syncOrAsync  [[#5878](https://github.com/plotly/plotly.js/pull/5878)], 
+   with thanks to @jklimke for the contribution!