LayerList API 4.3 obtain Id of the sublayer on toggle

[IsaacLañado]

Hi All,

I'm kind of new on the API 4.3 and I've bean searching everywhere but cant find the answer.

What I basically want to do is that when that all of my sublayers are not visible as default. When the user clicks a sublayer for viewing I would like to get the ID of the sublayer the user clicked so that I can refresh the search widget son that the user can search on the visible sublayer.

i read that with the ListItem you can grab it but i don't know how to invoque that parameter on click

Hope someone can help me.

Here is a snippet of how I'm loading the #LayerList‌

layer = new MapImageLayer({
            url: URL
        });

var view = new MapView({
            map: map,
            container: "viewDiv",
            extent: extent
        });

var layerList = new LayerList({
            view: view
        });

view.ui.add(layerList, "top-right");‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

[KristianEkenes · Accepted solution]

You would need to watch the visible property of the ListItem, then grab the ID of the sublayer when the value is true:

if (item.layer.declaredClass === "esri.layers.support.Sublayer") {
  watchUtils.whenTrue(item, "visible", function(newVal) {
    console.log("sub layer id of visible layer: ", item.layer.id);
  });
}‍‍‍‍‍

Here's a live app based on the SDK sample: https://codepen.io/kekenes/pen/zdxJpX?editors=1001