How to handle QueryTask call back function in AMD module?

SanajyJadhav

Hello,

 

I have just started learning ArcGIS API For JavaScript and Dojo AMD and I'm stuck on an issue of callback function of a query task.

 

I have a simple html page and couple of custom AMD modules inside a folder.Below is my folder structure.

 

Below is my AMD module for querying feature layer added to map and I call function "queryStatesLayer" from my index.html page.

 

define(["esri/tasks/QueryTask","esri/tasks/query","dojo/_base/lang"],function(QueryTask,Query,lang){     return{    queryStatesLayer:function (sqlString,Layer,outFlds){    var query,queryTask;    //initialize query task   queryTask = new QueryTask(Layer.url);    //initialize query   query = new Query();   query.returnGeometry = true;   query.outFields = outFlds;    //execute query   queryTask.execute(query,showResults);   },    //query completed Callback function.   showResults: function(qryResults){   alert("Query Completed..");  } ...    }; }); //define function ends..

 

Now,my problem is I'm not being able to figure out how should I write my query completed call back function in my module.I know that the way it is written now will not be called when query is completed. And if I write it as simple function outside of return { };it not recognized and I get an error in the console of Mozilla Firefox.

 

I would appreciate if I could get guidance on this issue.I want to write my query completed callback function in my custom AMD module.

 

S.

RRubalcava

The way you are doing it, you can just use an anonymous function in the execute method and it will work.

queryTask.execute(query, function(queryResults) { ... });

Or you could return the execute method.

return queryTask.execute(query);

Then whatever function called it could handle the callback.

myTaskObject.queryStatesLayer('NAME').then(function(queryResults) { ... });

The execute method of a QueryTask is a Promise, handled by dojo/Deferred.

I hope that helps.