[logicallee]

It would be nice if it indicated where it was making stuff up (in the zip code example, for the rows that were missing some data, it just makes it up - these rows are not distinguished visually from the rows where it did not add data not in the input.)

What I mean is if every row had a date like "12 May 2002" and you wanted it turned into 2002.05.12 then it would be nice if it indicated when it added data. For example if one of the rows just read "15 May" then, since there is no year, it would not be completely absurd if it transformed into 2017.05.15 - or if all of the other data is 2002, then adding that. But I really think silently adding data that was not in the input is going too far. A transform shouldn't ever silently inject plausible data with no indication that this is interpolated. Bad things can result.

Otherwise great demo!