Express GET http://localhost:3000/undefined 404 (Not Found)

I wrote the code according to the official website, but every get request appears
GET / undefined 404
I have no idea why get / undefined

Front-end node.js express
Feb.28,2022

this problem has been eliminated since the Firefox browser was changed.

I guess Chrome sent the request, but I just can't find it.

by closing the extension one by one, I found that this was caused by the crxMouse Chrome gesture.
turn off crxMouse and you don't have this problem.

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MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b32465-2bdf4.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b32465-2bdf4.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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