topic Re: Bug with dojo/on is version 3.7 in ArcGIS JavaScript Maps SDK Questions

Bug with dojo/on is version 3.7

ShawnHolyoak — Wed, 02 Oct 2013 14:06:10 GMT

In upgrading my application to version 3.7 of the api, I've run into what I believe is a bug. When I try to connect to the layers-add-result event for my map, I try to use the dojo/on amd method. My code for that is:

on(map, "layers-add-result", function(e) {   var toc = new agsjs.dijit.TOC({    map: map,    layerInfos:legendLayers   }, 'legendDiv');   toc.startup();  });

That returns an error "TypeError: Cannot read property 'tagName' of undefined ". When I try using the old dojo.connect method, though, everything works. My code using the old dojo.connect is:

dojo.connect(map,'onLayersAddResult', function(results){   var toc = new agsjs.dijit.TOC({    map: map,    layerInfos:legendLayers   }, 'legendDiv');   toc.startup();  });

According to the documents, version 3.7 is using dojo version 1.9.1, which should certainly support the dojo/on functionality. What, if anything, am I doing wrong. If I'm not doing anything wrong, how do I file a bug report?

Re: Bug with dojo/on is version 3.7

MattLane — Sun, 12 Dec 2021 02:46:07 GMT

Should it not be

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

Re: Bug with dojo/on is version 3.7

ShawnHolyoak — Wed, 02 Oct 2013 14:11:50 GMT

Not according to the dojo/on documentation, https://dojotoolkit.org/reference-guide/1.9/dojo/on.html

Re: Bug with dojo/on is version 3.7

JonathanUihlein — Sun, 12 Dec 2021 02:46:10 GMT

Both are valid.

map.on("layers-add-result", function(e) {
//stuff
});

on(map, "layers-add-result", function(e) {
//stuff
});

In that document holyoaks linked, there is another document linked at the bottom that discusses both uses.
https://dojotoolkit.org/reference-guide/1.9/dojo/Evented.html#dojo-evented

Map is an object that fires its own events, as explained here:
https://developers.arcgis.com/en/javascript/jsapi/map-amd.html

Now, onto troubleshooting...
Does the event fire?
What happens when you wrap the problematic code in a try/catch?

Re: Bug with dojo/on is version 3.7

ShawnHolyoak — Sun, 12 Dec 2021 02:46:13 GMT

Both are valid.
map.on("layers-add-result", function(e) {
//stuff
});

on(map, "layers-add-result", function(e) {
//stuff
});
Does the event fire?

What happens when you wrap the problematic code in a try/catch?

The error is caught, with the message originally mentioned, "Cannot read property 'tagName' of undefined". map.on(), though, as suggested by mattlane86, also works properly. So it seems it's the on(target, event, listener) style that is returning the error.

Re: Bug with dojo/on is version 3.7

JonathanUihlein — Wed, 02 Oct 2013 14:33:38 GMT

Are you able to fire the event with a simple console.log in the function block, like in this jsfiddle?

http://jsfiddle.net/NcCWw/

*edit

Also, you should probably be creating the TOC object earlier on in your code (preferably before the parser runs). You can still start it up inside your event.

Re: Bug with dojo/on is version 3.7

JeffPace — Wed, 02 Oct 2013 14:34:42 GMT

i have noticed similar issues with layers add

map.on works, on(map style does not

Re: Bug with dojo/on is version 3.7

ShawnHolyoak — Wed, 02 Oct 2013 14:37:43 GMT

Are you able to fire the event with a simple console.log in the function block, like in this jsfiddle?

http://jsfiddle.net/NcCWw/

*edit

Also, you should probably be creating the TOC object earlier on in your code (preferably before the parser runs). You can still start it up inside your event.

No. The event isn't fired. The error seems to be in attaching the event handler to the map.

Re: Bug with dojo/on is version 3.7

ShawnHolyoak — Wed, 02 Oct 2013 14:38:14 GMT

i have noticed similar issues with layers add

map.on works, on(map style does not

How do I file a bug report?

Re: Bug with dojo/on is version 3.7

JonathanUihlein — Wed, 02 Oct 2013 14:38:48 GMT

No. The event isn't fired. The error seems to be in attaching the event to the map.

Hmmm... could you replicate the issue with http://jsfiddle.net/ so I can take a look at your code?

Re: Bug with dojo/on is version 3.7

ShawnHolyoak — Wed, 02 Oct 2013 14:54:20 GMT

Hmmm... could you replicate the issue with http://jsfiddle.net/ so I can take a look at your code?

Hmm. I can't replicate it http://jsfiddle.net/NcCWw/7/. It's working in this instance. Just not working with my full code. I suppose it's possible that it's the TOC widget I'm using that's causing the issue.

Re: Bug with dojo/on is version 3.7

JonathanUihlein — Wed, 02 Oct 2013 15:18:54 GMT

Hmm. I can't replicate it http://jsfiddle.net/NcCWw/7/. It's working in this instance. Just not working with my full code. I suppose it's possible that it's the TOC widget I'm using that's causing the issue.

OK great! We've narrowed it down.
I would try initializing the TOC before my ready and parser calls, to make sure it's accessible when the page first loads.

Re: Bug with dojo/on is version 3.7

ShawnHolyoak — Wed, 02 Oct 2013 15:23:13 GMT

OK great! We've narrowed it down.
I would try initializing the TOC before my ready and parser calls, to make sure it's accessible when the page first loads.

I don't think I can do that. The TOC requires the map and an array of layers for its constructor, and since the map requires the divId to be created, I have to do that after domReady!, no?

Re: Bug with dojo/on is version 3.7

JeffPace — Wed, 02 Oct 2013 15:40:13 GMT

I:

1. create map
2. add layers
3. create toc on the "layers-add" event

this.map = new Map("map", {                                     infoWindow: popup,                                     basemap: "streets",                                     autoResize: true,                                     sliderStyle: style,                                     logo: false,                                     showAttribution: false,                                     lods: lods                                 });                                 map = this.map;     var tocAdder = map.on('layers-add-result', lang.hitch(this, function(results) {                                     // alert('in onlayeradd');                                     if (!this.toc) {                                         this.toc = new agsjs.dijit.TOC({                                             map: map,                                             layerInfos: layerInfos.reverse()                                         }, 'tocDiv');                                          toc = this.toc;                                         toc.startup();                                          lang.hitch(this, createLegend());

Re: Bug with dojo/on is version 3.7

JonathanUihlein — Wed, 02 Oct 2013 15:53:35 GMT

+1 to Jeff; he beat me to it!

@Holyoaks, when you find the final solution to your problem, make sure you mark this thread as answered.
Many people use nliu's TOC widget (it's great!) and this is a useful thread in case anyone runs into a similar problem.

Re: Bug with dojo/on is version 3.7

JeffPace — Wed, 02 Oct 2013 15:59:46 GMT

here's my version of it

http://www.mymanatee.org/gisapps/mapviewer/mobile/mobiletest.html

Warning: site in development

I made a couple small tweaks to it, and added functionality of loading layers from a set of json files.

You can change the layers that are currently loaded on the "settings" tab

Re: Bug with dojo/on is version 3.7

TracySchloss — Sun, 12 Dec 2021 02:46:15 GMT

I'm having an issue today with something similar, but my code is slightly older, 3.4. I have made no changes at all to this code for over a week and it was working as of yesterday. I have a dojo.connect on the map for onLayersAddResult, which is used to create the toc.

      map.addLayers([eezLayer, eezFeatureLayer]);  

  dojo.connect(map, 'onLayersAddResult', function(results) {
        var toc = new agsjs.dijit.TOC({
          map: map,
          layerInfos: [{
             layer: eezLayer,
            title: "Enhanced Enterprise Zones",
            slider:true 
          },{
            layer: districtLayer,
            title: "Legislative Districts"
          }]
        }, 'tocDiv');
        toc.startup();  
      });

This never executes because it never detects the onLayersAddResult event has fired. I'm completely baffled. This code has been in test for a month and today it suddenly decided not to work?!

The layers do get added, but I have no TOC because of this.

Re: Bug with dojo/on is version 3.7

JohnGravois — Thu, 03 Oct 2013 18:04:01 GMT

since the map class itself is evented, i'm not sure I understand the need to try and use 'dojo/on' to handle event wiring.

@tracy. also not sure whats causing your problem.

Re: Bug with dojo/on is version 3.7

TracySchloss — Thu, 03 Oct 2013 18:09:25 GMT

That turned out to be operator error. I had changed around the location of one of my services yesterday to be in the subfolder where it belonged. Since the layer wasn't really valid, then onLayersAddResult never fired.

I thought I'd changed all the places I used the layer, but I missed one. I'm developing my own mental list of Murphy's Laws. If you are 100% certain you've identified the line of code where your problem lies, there is a 100% certainty your problem lies elsewhere.

Re: Bug with dojo/on is version 3.7

ShawnHolyoak — Thu, 03 Oct 2013 20:01:04 GMT

since the map class itself is evented, i'm not sure I understand the need to try and use 'dojo/on' to handle event wiring.

@tracy. also not sure whats causing your problem.

Because esri says it uses dojo 1.9.1 which allows it, but more importantly, not all esri objects seem to be evented (e.g., the navigation toolbar).