run demo online throw error

[wszgrcy]

Describe the bug
I am trying to learn how to use dnd
run demo online
Execution looks very successful
When I execute code locally,Found an error message
Then I opened the console on the webpage and found that the demo on the official website also had this error message

Reproduction
online demo online

Steps to reproduce the behavior:

1. F12
2. drap and drop a box

Expected behavior
Demo appears to be running normally, but the console threw an exception. I'm not sure if this will affect development
Screenshots

Desktop (please complete the following information):

• OS: linux ubuntu 22.04
• Browser [e.g. chrome, safari] chrome
• Version [e.g. 22] 123

Additional context