`Nan` on date when defining a format

Hello. I have a timestmap column in a datatable for which I defined a format. When I do that and I have a non-date in the table, it renders: NaN/NaN/NaN NaN:NaN:NaN.

Which is strange for me, since the behaviour of the normal format is to render whatever the column is without transforming it into a date, as we can see in this example: https://snippet.webix.com/0xcta0op

What can I do to define a format and have the same behavior ?

Hello,
Please note that instead of format: webix.i18n.DateFormatStr correctly will be usingformat: webix.i18n.dateFormatStr . So in both datatables will be NaN in the snippet.
You can use format as a function (as well as in template).
Depending on condition, you can return also
webix.i18n.fullDateFormatStr(new Date())
Here is info about formatting methods .