How to use dynamic layers in js api 4.4

Question

I'm confused on how I can use dynamic layers in the 4.4 api. I have a group of layers published from arcmap like this: By default, all of the group layers are off, some of the child layers are on, and nothing is visible until the user toggles a group layer on. (this is how it works in 3.x). In 4.4, I set up some layer like this: { id: 'assets', url: `${url}/internal/assets/MapServer`, // sublayers: [{ // id: 12, // visible: true // }, { // id: 13, // visible: true // }], popupTemplate: { title: 'cid: {cid}' } }‍‍‍‍‍‍‍‍‍‍‍‍‍‍ When the map loads, all of the child layers that are visible are displayed. The map looks crazy busy. So just to test what happens I uncomment the above code to show only sublayer 12. This works, only sublayer 12 is shown: Now if I uncomment both sublayers 12 and 13 from the block above, it stops working. I get no image from the server. I checked the network logs. In the version with no sublayers, the network image request looks like this: layers:show:43,44,51,50,36,37,38,1,2,3,53,54,6,8,9,10,55,13,14,15,16,17,22,58,59,25,30,31,32,33‍ With one sublayer: layers:show:12‍ With two sublayers: dynamicLayers:[{"id":13,"source":{"mapLayerId":13,"type":"mapLayer"}},{"id":12,"source":{"mapLayerId":12,"type":"mapLayer"}}]‍ My questions are: * Why does providing no sublayers display the layer incorrectly (ie ignoring group layer visibility)? * Why do the parameters change from layers to dynamicLayers when switching from one sublayer to two sublayers? - a similar problem is observed here: https://codepen.io/anon/pen/zdpGLL?&editors=100

roemhildtg · Answer

From the chat:

roemhildtg [10:42 AM] 
Its like its getting reversed somehow

yann [10:56 AM] 
well yes and no :slightly_smiling_face:

[10:56] 
the ids are one order. but overall, all the layers and sublayers in the map are ordered the same way, drawing from bottom to top

ThomasSolow · Answer

Good to know you've got it working.

Ideally the server wouldn't return 200 and an error.  I'm not sure what that's about, but maybe it's unavoidable.

Would be interested to know why the order of the sublayers matter.

roemhildtg · Answer

Thanks for the tips. Just an Update: If I specify the sublayers in reverse order like this: sublayers: [{ id: 13, visible: true }, { id: 12, visible: true }],‍‍‍‍‍‍‍ It actually works! Thanks to Yann Cabon‌ for this tip. Just to address some of your comments: > The JS code then looks at this information and see that there is no sublayer with id 12 There is a sublayer id 12. Its the storm structures layer. > Anyway, the request is made and fails, and that failure is not handled correctly, so there's no user feedback. The request appears to succeed, the server returns a status 200, but there is "No Data" in the request. Server logs on debug mode don't show any issues either. If I open up the url, the data does show an error message: {"error":{"code":400,"message":"'dynamicLayers' is not enabled on this MapService.","details":[]}} > I assume all of your sublayers are sourced from the same Map Service, so you shouldn't need to worry about dynamicLayers at all. Correct, I don't actually want to use dynamic layers, I just want the default symbology, but for some reason the api is converting my request to a dynamic layers request.