Following this week's train a sudden error spike was observed that was limited to da.m.wikipedia.org
It quickly resolved itself. This week's train removed the mediawiki.viewport library from the code path, so this would suggest that old RelatedArticles code was loaded with the old list of module dependencies. This might point to a ResourceLoader issue.
{F34730431}
https://logstash.wikimedia.org/app/dashboards#/doc/logstash-*/logstash-2021.11.04?id=1vN_7HwB1RMACsoSHaqJ
==== Error ====
* mwversion: `undefined`
* reqId: `undefined`
* [[ https://logstash.wikimedia.org/app/dashboards#/view/AXFV7JE83bOlOASGccsT?_g=(time:(from:'2021-11-03T20:33:02.480Z',to:'2021-11-04T20:33:02.480Z'))&_a=(query:(query_string:(query:'reqId:%22undefined%22'))) | Find reqId in Logstash ]]
* [[ https://logstash.wikimedia.org/app/dashboards#/view/AXFV7JE83bOlOASGccsT?_g=(time:(from:now-30d,to:now))&_a=(query:(query_string:(query:'normalized_message:%22TypeError:%20Cannot%20read%20properties%20of%20undefined%20(reading%20'isElementCloseToViewport')%22'))) | Find normalized_message in Logstash ]]
```name=normalized_message
TypeError: Cannot read properties of undefined (reading 'isElementCloseToViewport')
```
```
name=exception.trace,lines=10
```
==== Impact ====
==== Notes ====