[GIS] evt.layers undefined while trying to display Legend widget in Javascript API

arcgis-javascript-apifeature-layerlegend

I cannot get an ArcGIS Javascript API Legend widget to show up. An excerpt of my code is as follows. I believe I'm failing somewhere near the console.log that I call…undefined comes up in the console at this point. So for some reason evt.layers is not getting populated. Have I provided enough code? If you need more snippets I can copy/paste more.

        parser.parse();

        //initialize the map object
        map = new Map("map", {
            basemap:"gray",
            center: [-96.53, 38.374],
            zoom: 13
        });

        //access the hydro layer as a feature layer
        var hydro = new FeatureLayer("http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/Hydrography/Watershed173811/MapServer/0", {
            mode: FeatureLayer.MODE_ONDEMAND,
            outFields: ["*"]
        });

        //add hydro to map
        map.on("layer-add-result", function (evt) {
            console.log(evt.layers);
            var layerInfo = arrayUtils.map(evt.layers, function (layer, index) {
                return {layer:layer.layer, title:layer.layer.name};
            });
            if (layerInfo.length > 0) {
                var legendDijit = new Legend({
                    map: map,
                    layerInfos: layerInfo
                }, "legendDiv");
                legendDijit.startup();
            }
        });
        map.addLayers([hydro]);
    });

Best Answer

To expand on your answer, you could fix it one of two ways:

map.on("layers-add-result", function (evt) {

This works because layers-add-result only fires when calling the map.addLayers() function, which expects an array of map layers.

You could have kept layer-add-result which fires any time a single map layer is added. To add a single layer, use the singular function map.addLayer(hydro)

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