Why doesn't an arcade expression work on a mapImageLayer

JackFairfield

When I apply an arcade expression to the value expression property of my unique value renderer, it doesn't seem to work as expected.

Here is a jsbin example using a modifyed sample that esri provides:

JS Bin - Collaborative JavaScript Debugging 

Here is the line in question:

valueExpression: "When($feature.type == 'Gravel', 'test')",

I would expect this to filter the layer down and only show 7 features, just like when the filter is applied in the rest endpoint. 

But instead, all of the features in the map adopt the uvr symbol:

MunachisoOgbuchiekwe

Hello Jack, 

As per documentation, Arcade expressions are not supported with MapImageLayers. Only FeatureLayers and SceneLayers are supported.