topic Re: querytask returns no errors but undefined variables! in ArcGIS JavaScript Maps SDK Questions

querytask returns no errors but undefined variables!

LefterisKoumis — Tue, 30 Jun 2015 23:42:50 GMT

This function returns undefined variable. The first alert returns: something found:1

the second alert returns "Odometer 1: undefined.

I have a very similar code shown below under GOOD CODE that it returns the expected value.

Both code execute the same querytask.

What's wrong in the first block code? Thanks.

function queryTask_odometer1_executeCompleteHandler(results)

{

if (results.features && results.features.length > 0) {

alert("something found: " + results.features.length);

resultCount=results.features.length;

for (var i = 0; i < resultCount; i++) {

var featureAttributes = results.features.attributes;

for (var attr in featureAttributes) {

if (attr = "Odometer")

{ alert(attr + "1: " + featureAttributes[attr]);

}

}else{

alert("nothing found");

}

//alert(mydata);

}

GOOD CODE

function showResults (results) {

var resultItems = [];

var resultCount = results.features.length;

alert (resultCount);

for (var i = 0; i < resultCount; i++) {

var featureAttributes = results.features.attributes;

for (var attr in featureAttributes) {

if (attr = "Odometer")

{ alert(attr + "1: " + featureAttributes[attr]);

resultItems.push("<b>" + attr + ":</b> " + featureAttributes[attr] + "<br>");

}

// dom.byId("info").innerHTML = resultI

Re: querytask returns no errors but undefined variables!

RobertScheitlin__GISP — Sat, 11 Dec 2021 16:08:34 GMT

Lefteris,

Your issue is that your are making an assignment to attr by using a single equal sign to evaluate a condition you must use a double or triple equal sign:

if (attr === "Odometer") {
  alert(attr + "1:  " + featureAttributes[attr]);
}

Re: querytask returns no errors but undefined variables!

OwenEarley — Wed, 01 Jul 2015 05:00:12 GMT

This issue occurs in the Good Code block as well.

Re: querytask returns no errors but undefined variables!

LefterisKoumis — Wed, 01 Jul 2015 15:14:19 GMT

Actually, no. I get a response with the correct value.

Thanks.

Here is the complete good code, modified from one of the samples in the esri's JS API website.

<!DOCTYPE html>

<html>

<head>

<!--The viewport meta tag is used to improve the presentation and behavior of the samples

on iOS devices-->

<title>Query State Info without Map</title>

require([

"dojo/dom", "dojo/on",

"esri/tasks/query", "esri/tasks/QueryTask", "dojo/domReady!"

], function (dom, on, Query, QueryTask) {

var queryTask = new QueryTask("<place you url>);

var query = new Query();

query.returnGeometry = false;

query.outFields = ["Odometer"];

on(dom.byId("execute"), "click", execute);

function execute () {

query.where = <place your condition> ;

queryTask.execute(query, showResults);

}

function showResults (results) {

var resultItems = [];

var resultCount = results.features.length;

alert (resultCount);

for (var i = 0; i < resultCount; i++) {

var featureAttributes = results.features.attributes;

for (var attr in featureAttributes) {

if (attr = "Odometer")

{ alert(attr + "1: " + featureAttributes[attr]);

resultItems.push("<b>" + attr + ":</b> " + featureAttributes[attr] + "<br>");

}

resultItems.push("<br>");

}

// dom.byId("info").innerHTML = resultItems.join("");

}

});

</script>

</head>

<body>

US state name :

<br />

</div>

</body>

</html>

Re: querytask returns no errors but undefined variables!

LefterisKoumis — Wed, 01 Jul 2015 15:18:45 GMT

Thanks. I agree, however the issue persists even after the correction. The strange thing is that the Good code even though has the same incorrect evaluation (attr = "Odometer"), it does work by providing a response with the correct value.

Re: querytask returns no errors but undefined variables!

RobertScheitlin__GISP — Wed, 01 Jul 2015 15:25:06 GMT

Lefteris,

Sure it would work as long as the query has a "Odometer" attribute in the results. Nothing is really jumping out at me as to why one would work and the other would not Assuming that both use the same exact Query where clause and same outfields. Can you provide more code for review?

Re: querytask returns no errors but undefined variables!

LefterisKoumis — Wed, 01 Jul 2015 16:00:06 GMT

Sure. Here is the "bad code". I already posted the good code in another response. I ensure you that the "where" and "url" lines are identical in both good and bad code since I copied and pasted. Thank you.

<!DOCTYPE html>

<html>

<head>

<!--The viewport meta tag is used to improve the presentation and behavior of the samples

on iOS devices-->

<title>Shapes and Symbols</title>

<style>

#info {

top: 20px;

color: #444;

height: auto;

font-family: arial;

right: 20px;

margin: 5px;

padding: 10px;

position: absolute;

width: 115px;

z-index: 40;

border: solid 2px #666;

border-radius: 4px;

background-color: #fff;

}

html, body, #mapDiv {

padding:0;

margin:0;

height:100%;

}

button {

display: block;

}

</style>

var map;

require([

"esri/map",

"esri/layers/DynamicMapServiceLayer",

"esri/tasks/QueryTask",

"esri/tasks/query",

"esri/symbols/SimpleMarkerSymbol",

"esri/tasks/FeatureSet",

"esri/InfoTemplate",

"dojo/_base/Color",

"dojo/dom",

"dojo/on",

"dojo/domReady!"

], function(

Map, DynamicMapServiceLayer, QueryTask, Query, SimpleMarkerSymbol, FeatureSet, InfoTemplate, Color, dom, on

) {

map = new Map("mapDiv", {

basemap: "streets",

center: [-25.312, 34.307],

zoom: 3

});

map.on("load", readurl);

function readurl() {

var queryTask_odometer1 = new QueryTask("<place you url>);

var queryTask_odometerParams1 = new Query();

queryTask_odometerParams1.geometry = false;

queryTask_odometerParams1.outfields=["Odometer"];

queryTask_odometerParams1.where= <place your condition> ;

//if (map.loaded) {

queryTask_odometer1.execute(queryTask_odometerParams1,queryTask_odometer1_executeCompleteHandler,onError);

//} else {

// map.on("load", function () {

// queryTask_odometer1.execute(queryTask_odometerParams1,queryTask_odometer1_executeCompleteHandler,onError);

// });

}

function onError(error) {

console.log(error);

}

function queryTask_odometer1_executeCompleteHandler(results)

{

if (results.features && results.features.length > 0) {

alert("something found: " + results.features.length);

resultCount=results.features.length;

for (var i = 0; i < resultCount; i++) {

var featureAttributes = results.features.attributes;

for (var attr in featureAttributes) {

if (attr === "Odometer")

{ alert(attr + "1: " + featureAttributes[attr]);

}

}else{

alert("nothing found");

}

//alert(mydata);

}

});

</script>

</head>

<body>

</body>

</html>

Re: querytask returns no errors but undefined variables!

RobertScheitlin__GISP — Wed, 01 Jul 2015 16:07:24 GMT

Lefteris,

I know you are trying to protect your data but can you show me what your condition looks like?

queryTask_odometerParams1.where = < place your condition > ;

Re: querytask returns no errors but undefined variables!

LefterisKoumis — Wed, 01 Jul 2015 16:19:09 GMT

Here is:

_County_selectedItem= "ALA";

_Route_selectedItem= 112;

_PM1_selectedItem= 0.5;

queryTask_odometerParams1.where= "County = '" + _County_selectedItem + "'" + " AND Route = " + _Route_selectedItem+ " AND PMc = '" + _PM1_selectedItem + "'" ;

However, I think I am getting close. The root of the problem is the loop

for (var attr in featureAttributes)

If I remove the condition,

for (var attr in featureAttributes) {

//if (attr === "Odometer")

//{

alert(attr + "1: " + featureAttributes[attr]);

// }

Then the alert shows only the first attribute which is not the Odometer. That explains, why I get no response.

Why the loop does not iterate through the rest of the attributes and stops at the first one. The bizarre point is that in the good code, when I used attr = "Odometer", it displays the value just fine!!

Re: querytask returns no errors but undefined variables!

RobertScheitlin__GISP — Wed, 01 Jul 2015 16:24:12 GMT

Lefteris,

OK I found the problem is was a CaSe issue.

You have outfields all lower case:

queryTask_odometerParams1.outfields=["Odometer"];

When the property is actually outFields with a capital F

queryTask_odometerParams1.outFields = ["Odometer"];

What this caused is no fields beside the display field to be returned by the query.

Re: querytask returns no errors but undefined variables!

LefterisKoumis — Wed, 01 Jul 2015 16:31:16 GMT

THANK YOU. I am so pissed at myself.

This is why JS needs a good IDE to capture silly mistakes like this. Oh boy, do I miss my flash builder.....

Re: querytask returns no errors but undefined variables!

BenFousek — Wed, 01 Jul 2015 17:08:34 GMT

There are many good editors with real time linting. I like Sublime Text - Download with SublimeLinter.

Also tasking running with Grunt: The JavaScript Task Runner

Esri has the .jshintrc (linting rules) file they use here jsapi-resources/jshint at master · Esri/jsapi-resources · GitHub

Re: querytask returns no errors but undefined variables!

LefterisKoumis — Wed, 01 Jul 2015 19:07:09 GMT

Thanks. I downloaded and use webstorm. I followed instructions including uploading esrijs typescript library, but still didn't catch the case error of the script posted above.