Ian,
Sure here is a sample that does just that:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no">
<title>Layer List Dijit</title>
<link rel="stylesheet" href="https://js.arcgis.com/3.16/dijit/themes/claro/claro.css">
<link rel="stylesheet" href="https://js.arcgis.com/3.16/esri/css/esri.css">
<style>
html, body, .container, #map {
height:100%;
width:100%;
margin:0;
padding:0;
margin:0;
font-family: "Open Sans";
}
#map {
padding:0;
}
#layerListPane{
width:25%;
}
.esriLayer{
background-color: #fff;
}
.esriLayerList .esriList{
border-top:none;
}
.esriLayerList .esriTitle {
background-color: #fff;
border-bottom:none;
}
.esriLayerList .esriList ul{
background-color: #fff;
}
</style>
<script>var dojoConfig = { parseOnLoad: true };</script>
<script src="https://js.arcgis.com/3.16/"></script>
<script>
require([
"esri/map",
"esri/layers/ArcGISDynamicMapServiceLayer",
"esri/dijit/LayerList",
"dojo/query",
"dojo/dom-class",
"dijit/layout/BorderContainer",
"dijit/layout/ContentPane",
"dojo/domReady!"
], function(
Map,
ArcGISDynamicMapServiceLayer,
LayerList,
query,
domClass
) {
var map = new Map("map", {
basemap: "topo",
center: [-123, 47],
zoom: 8,
sliderStyle: "small"
});
var atlasLayer = new ArcGISDynamicMapServiceLayer("http://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer", {
"id": "atlasLayer",
"showAttribution": false
});
var recreationLayer = new ArcGISDynamicMapServiceLayer("http://sampleserver6.arcgisonline.com/arcgis/rest/services/Recreation/MapServer", {
"id": "recreationLayer",
"showAttribution": false
});
var waterNetLayer = new ArcGISDynamicMapServiceLayer("http://sampleserver6.arcgisonline.com/arcgis/rest/services/Water_Network/MapServer", {
"id": "waterNetworkLayer",
"showAttribution": false
})
map.addLayers([atlasLayer, recreationLayer, waterNetLayer]);
var llWidget = new LayerList({
map: map,
layers: [{
layer: atlasLayer,
id: "Atlas layers",
subLayers: true
},
{
layer: recreationLayer,
id: "Recreation layers",
subLayers: true
},
{
layer: waterNetLayer,
id: "Water Network layers",
subLayers: true
}],
showSubLayers: true,
showOpacitySlider: true,
showLegend: true
},"layerList");
llWidget.startup();
llWidget.on('load', function(){
expandLayerList();
});
function expandLayerList() {
query('.esriTabMenu').forEach(function(node){
//console.info(node);
var nEntry = node.getElementsByTagName('li');
//console.info(nEntry);
var nEntryArray = Array.prototype.slice.call(nEntry, 0);
//console.info(nEntryArray);
var sublayers = nEntryArray.shift();
nEntryArray.splice(1,0,sublayers);
while (node.lastChild){
node.removeChild(node.lastChild);
}
for (i=0; i<nEntryArray.length; i++){
node.appendChild(nEntryArray);
}
});
//This first part will expand the main layers.
query('.esriLayer').forEach(function(node){
domClass.add(node, "esriListExpand");
});
query('.esriToggleButton').forEach(function(node){
domClass.replace(node, "esri-icon-down", "esri-icon-right");
});
//This part will collapse the sublayer lists
query('.esriSubListLayer.esriHasSubList.esriSubListExpand.esriListVisible').forEach(function(node){
//console.info(node);
domClass.remove(node, "esriSubListExpand");
domClass.remove(node, "esriListVisible");
});
}
});
</script>
</head>
<body class="claro">
<div class="container" data-dojo-type="dijit/layout/BorderContainer"
data-dojo-props="design:'headline',gutters:false">
<div id="layerListPane" data-dojo-type="dijit/layout/ContentPane" data-dojo-props="region:'right'">
<div id="layerList"></div>
</div>
<div id="map" data-dojo-type="dijit/layout/ContentPane" data-dojo-props="region:'center'"></div>
</div>
</body>
</html>
