conduktor console: how can I filter on the message timestamp with a JS Filter

Question

I am using the conduktor console to browse our kafka topics. I want to filter on the message timestamp, e.g. older than xy, how can this be done using a js filter? I tried:

return value.timestamp < 1673541484

and

return timestamp < 1673541484

But this didn't work. I neither found a sample in the docs:

https://docs.conduktor.io/platform/console/features/browse-data/#filtering