The autocomplete feature currently only has partial coverage of available functions. In general, if it’s a native JS function/ method - you can use it in n8n.
We should be releasing rolling improvements on the autocomplete feature over the next weeks and months, including more function coverage.
It’s strange. First of all, before writing here, I tried to type without looking to autocomplete, but got an error. But now, I retry and it’s ok… May be it’s because there was nothing in input side at the first time.
@orth if you didn’t have any input data yet, that would be why. FYI: in a future phase we plan to add not only expression errors but warnings. So once that’s added, you’d get a more specific warning that it could be due to no input data.