Esri JSAPI layer to support STYLES argument on WMSLayer

StyledWMSLayer.js

define([
  "dojo/_base/array",
  "dojo/_base/declare",
  "dojo/_base/lang",
  "esri/layers/WMSLayer"
], function(
  array,
  declare,
  lang,
  WMSLayer
) {

  /*
   * for each WMSLayerInfo, a "style" property has been added to indicate the 
   * active style for the individual layer. update the layerInfo's style property
   * and finish with a call to layer::refresh() to update the layer in the map.
   */

  var StyledWMSLayer = declare(WMSLayer, {
    getImageUrl: function(extent, width, height, callback) {
      WMSLayer.prototype.apply(this, [
        extent,
        width,
        height,
        lang.hitch(this, function(url) {
          url = url.replace("STYLES=&", lang.replace("STYLES={styles}&", {
            styles: array.map(array.filter(this.layerInfos, function(li) {
              return this.visibleLayers.indexOf(li.name) !== -1;
            }, this), function(li) {
              return li.style;
            })
          }));
          callback(url);
        })
      ]);
    }
  });

  return StyledWMSLayer;
});

Hi Jim, thanks for sharing. Could not get your code running , so I did a similar stunt based on Esri´s custom layer example:

dojo.declare("StyledWMSLayer", esri.layers.WMSLayer, {
    constructor: function() {
        this.onLoad(this);
    },

    getImageUrl: function(extent, width, height, callback) {
        var params = {
            request: "GetMap",
            format: this.imageFormat,
            layers: this.visibleLayers,
            styles: "styles",

            bbox:extent.xmin + "," + extent.ymin + "," + extent.xmax + "," + extent.ymax,
            srs: "EPSG:" + extent.spatialReference.wkid,
            width: width,
            height: height
        };

        callback(this.url + "&" + dojo.objectToQuery(params));
    }
});