How can i make query with a predicate that tests null column in Breeze?

Question

How can I make a query with a predicate that tests for null in Breeze?

with a Predicate.create("region", "==", null)

I get an 500 http error from server:

Unable to perform operation: eqon types:

I am using the Asp.Net Breeze Web Api Controller

Answer 1

Predicate expressions for null data property values do work as in your example, but I am guessing that in your query "region" is an instance of the region type. I will look into this in more detail, but for the time being I am guessing that you also have a "regionID" property or something like it. So maybe try:

EntityQuery.from("Territories").where("regionID", "==", null)