Access Layer Properties for WebMap Layers

[StefanFreelan]

Hi All,

I've got a working webmap (JS 4.24), using an AGOL web map but I can't figure out how to access the individual layers contained in the webmap. I just want to be able to reference a specific layer so I can do things like toggle it's visibility.

I've tried a couple of methods (see below), but if they are working I haven't been able to find a way to then reference the layer (where do I put the visible: true, statement? Or the listMode: 'hide' statement?

Obviously I'm fairly new to JavaScript...

Is there a better way to reference a layer in a webmap?

Having referenced it, how do I set it's properties?

Any advice or suggestions appreciated,

thanks,

~stefan

Stuff I've tried:

const webmap = new WebMap({
portalItem: {
id: "9c161033f604436193805a7484feab3d" // Web Map for JavaScript
}

});

const view = new MapView({
container: "viewDiv",
map: webmap,
});

// get layers when the view is initialized
webmap.when(() => {
// layer 0
const layer0 = webmap.layers.items[0];
});

// OR Find a layer by ID...
const layer1 = webmap.findLayerById("958f6534812a4407925a2a18a640b841");

[UndralBatsukh]

Hi there, 

You can loop through all operational layers in your web map after all resources are laded and find the layer you need.  The following code should get you started: 

webmap.loadAll().then(()=>{
  // loop through all operational layers in your webmap
  webmap.layers.forEach((layer)=>{
    console.log("layer.id", layer.id, layer);
    // check your layer here
  });
 });

This sample also shows how to get a layer at the specified index. https://developers.arcgis.com/javascript/latest/sample-code/sandbox/?sample=featureeffect-drop-shado...

[StefanFreelanFreelan]

Thanks UndralBatsukh, I'll see if I can get this to work.

[Jeff-Reinhart]

Thanks! This helped with a different timing issue I was having where the map.allLayers.items[0].renderer.uniqueValueInfos was coming up undefined.