topic Re: How do I evaluate a layer name? in ArcGIS JavaScript Maps SDK Questions

How do I evaluate a layer name?

ChrisSergent — Sat, 11 Dec 2021 19:20:08 GMT

I have the following code that defines my feature layers, but I would like to evaluate the layer name to ensure that the numbered layer is the correct feature that I am referencing on the chance layers are added. How would I do this?

var initialExtent = new Extent({
        "xmin": 777229.03,
        "ymin": 1133467.92,
        "xmax": 848340.14,
        "ymax": 1185634.58,
        "spatialReference": {
            "wkid": 3435
        }
    });
    // app configuration  
    var config = {


        mapOptions: {
            showAttribution: false,
            sliderStyle: "small",
            extent: initialExtent,
            logo: false,
            sliderPosition: "bottom-right"
        },


        signLayerUrl: "http://maps.decaturil.gov/arcgis/rest/services/test/StreetSignTest/FeatureServer/0",
        
        supportLayerUrl: "http://maps.decaturil.gov/arcgis/rest/services/test/StreetSignTest/FeatureServer/1"


    };

I tried doing the following:

var featureService = new FeatureLayer("http://maps.decaturil.gov/arcgis/rest/services/test/StreetSignTest/FeatureServer");

alert(featureService.LayerInfo[0].name);

And receive the following error:

"in domReady callback"

"TypeError: Cannot read property '0' of undefined

I thought that this would provide me with the name of the first layer, but I am receiving an error instead. How should I write this?

And I referenced this, but there are no examples: LayerInfo | API Reference | ArcGIS API for JavaScript

Re: How do I evaluate a layer name?

RobertScheitlin__GISP — Mon, 11 May 2015 15:21:33 GMT

Chris,

You need to wait for the FeatureLayer load event before you can check properties.

Re: How do I evaluate a layer name?

KenBuja — Sat, 11 Dec 2021 19:20:10 GMT

This syntax will give you the name of your featureLayer

featureLayer.on("load", function() {
    console.log(featureLayer.name);
});

Re: How do I evaluate a layer name?

ChrisSergent — Mon, 11 May 2015 19:32:38 GMT

Ken and Robert Scheitlin, GISP I have the JSON information here: http://maps.decaturil.gov/arcgis/rest/services/test/StreetSignTest/FeatureServer/0?f=pjson

and I want the name of this layer. Do you know how to get the value from the name of name, which would be the name of the layer.

Re: How do I evaluate a layer name?

RobertScheitlin__GISP — Sat, 11 Dec 2021 19:20:13 GMT

Chris,

Do you mean work with the raw layer json?

        var requestHandle = esriRequest({
          url: "http://maps.decaturil.gov/arcgis/rest/services/test/StreetSignTest/FeatureServer/0",
          content: {
            f: 'json'
          },
          handleAs: "json"
        });

        requestHandle.then(function(lyrJSON, io){
          console.info(lyrJSON.name);
        }

Re: How do I evaluate a layer name?

ChrisSergent — Mon, 11 May 2015 20:11:17 GMT

Yes, this gets me a layer name. I would basically want to say something like:

If lryJSON.name = "sign" then app.signLayer = "http://maps.decaturil.gov/arcgis/rest/services/test/StreetSignTest/FeatureServer/0"

That way I can assign layers based on verified names in the event that they are moved. Do you know what I would need to add?

Re: How do I evaluate a layer name?

KenBuja — Mon, 11 May 2015 20:41:33 GMT

If you're getting the layer information on the entire feature service, then why not use the layers to give you the id number? Your service (http://maps.decaturil.gov/arcgis/rest/services/test/StreetSignTest/FeatureServer) returns the following JSON

{
"currentVersion": 10.2,
"serviceDescription": "Test service for Street Signs.",
"hasVersionedData": true,
"supportsDisconnectedEditing": true,
"syncEnabled": false,
"supportedQueryFormats": "JSON, AMF",
"maxRecordCount": 1000,
"capabilities": "Create,Query,Update,Uploads,Editing",
"description": "",
"copyrightText": "",
"spatialReference": {
    "wkid": 102671,
    "latestWkid": 3435
},
"initialExtent": {
    "xmin": 774645.2192425077,
    "ymin": 1152044.6375970563,
    "xmax": 852104.4261770676,
    "ymax": 1185177.4775575039,
    "spatialReference": {
      "wkid": 102671,
      "latestWkid": 3435
    }
},
"fullExtent": {
    "xmin": 788974.3070424125,
    "ymin": 1140570.7070784047,
    "xmax": 837775.3383771628,
    "ymax": 1186701.6062862352,
    "spatialReference": {
      "wkid": 102671,
      "latestWkid": 3435
    }
},
"allowGeometryUpdates": true,
"units": "esriFeet",
"documentInfo": {
    "Title": "",
    "Author": "",
    "Comments": "Test service for Street Signs.",
    "Subject": "Test service for Street Signs.",
    "Category": "",
    "Keywords": "Street Signs"
},
"layers": [
    {
      "id": 0,
      "name": "Sign"
    },
    {
      "id": 1,
      "name": "Support"
    }
],
"tables": [],
"enableZDefaults": false
}

Check the "layers" array and if name==="Sign", then you have the correct id to use. You don't have to worry about layers being inserted and changing the ids.