Can you use Arcade to change a field type from Text to Date on the fly for use with a dashboard date selector? I see how it can be done in a pop up, but that doesn't interact with the date selector.
It looks like a data expression would work. Are there any examples similar to my use case?
yeh I'd definitely say a data expression. Syntax would be exactly the same as the popup, except that you would reference the feature first by something like:
(abridged example from Data Functions | ArcGIS for Developers)
var portal = Portal('https://www.arcgis.com'); var features = FeatureSetByPortalItem(portal, '7b1fb95ab77f40bf8aa09c8b59045449')
I can't really offer you an example of the date string to datetime/Esri date without knowing what the string looks like, but here are some example methods Date Functions | ArcGIS for Developers.
Unfortunately, you can't get Arcade to work like that in the dashboard. A date selector is "layer agnostic", so to speak, and can't work with non-attribute data, as it is essentially just submitting an SQL query to the feature service.
If you watch the network traffic on your browser, you can see it happen:
Picking that option sends this to request (relevant part bolded):
"where":"(sale_date>timestamp '2006-01-02 05:59:59' AND valid_sale=0) AND (sale_date BETWEEN timestamp '2020-01-01 06:00:00' AND timestamp '2021-01-01 05:59:59')"
The only way to get a date filter to work would be to create a true date field. You wouldn't be the first person to create a new field for the sake of a dashboard!
Does the text field consistently contain date values? And is there a reason to maintain it as a text field instead of just converting it?
On looking at the question again, it's not going to be easy, but theoretically you could iterate through the original values and create a text representation of the JSON to create a new feature set with all the existing and new date values - but it's far from trivial.