Fix an issue on excel custom-function about data formatting on date/time
User can't customise date format of the data that has been rendered by custom-function - dynamic array formula.
for more info: https://github.com/OfficeDev/office-js/issues/1068
Viktor Antonov commented
more generally - it would great to have a possibility to set numberFormat from main code or custom function code.
I'm not just talking about a mask like 'dd-mm-yyyy', or '@', or '### ## 0. ##', but about a really set type like 'date' / as an example - a result of standard function '=Date', where we get formatted date and the cell has numberFormat == short date, but it is still date in OLE Automation date format