How to pass arguments to query function in different module

Question

I have a query (see this jsbin example) to find the percentile rank of a fields value. So it finds all records (N) and then how many records are less than itself (k). Percentile = k/N as a rounded percent.

The math is working correctly, but I would like to use the whole thing a function to which I could pass arguments for field name and field value when you click on features.

My problem is this: I have the listeners for selecting features outside of the AMD module where I have the query. So if the listeners call this percentile function, it is undefined. However, if I move this function outside the AMD module, then query and QueryTask are undefined, because I set those up in the module.

I'm new to Javascript modules, so I'm hoping to find out if there is a simple way I could avoid this problem. I've tried moving the listeners inside the AMD module, but that makes other functions undefined.

I may not be using the word module correctly here. I think what I'm experiencing is a scope problem. I have declared this function in one scope and I'm trying to access it in another. Is that the right way to think about it?

Here is the complete code:

function pctile(pctileField,pctileValue) {

    queryTaskN = new QueryTask("http://gis.datadrivendetroit.org/arcgis/rest/services/DetroitNeighborhoodMetrics/FeatureServer/0");
    queryN = new Query();
    queryN.where = '1=1';
    queryTaskN.executeForCount(queryN, storeResultsN);

    function storeResultsN(results) {
        N = results;
        console.log("N:",N);
    };

    queryTaskN.on("execute-for-count-complete", function() {
        queryTaskK = new QueryTask("http://gis.datadrivendetroit.org/arcgis/rest/services/DetroitNeighborhoodMetrics/FeatureServer/0");
        queryK = new Query();
        queryK.where = '"'+pctileField+'" > ' + pctileValue;
        queryTaskK.executeForCount(queryK, storeResultsK);

        function storeResultsK(results) {
            k = results;
            console.log("k:",k);
            p = k / N;
            console.log(p);
            P = p*100;
        };
    });
};

Answer 1

The two passed parameters are not recognized in the scope of the listeners.

You've mentioned that you declared a function inside the same AMD, so you have just to create globale variables and use them inside callback functions.

try this code: (results shown in console)

require([
  "dojo/parser","esri/tasks/QueryTask","esri/tasks/query",

], function(
  parser,QueryTask,Query
) {
  parser.parse();
  //declaring globale varibales N ,pctileField and pctileValue 
  this.N = 0;
  this.pctileField = "";
  this.pctileValue = "";

  queryTaskN = new QueryTask("http://gis.datadrivendetroit.org/arcgis/rest/services/DetroitNeighborhoodMetrics/FeatureServer/0");
  function pctile(pctileField,pctileValue) {
    // assigning passed arg values to the globale variable
    this.pctileField = pctileField;
    this.pctileValue = pctileValue;

    queryN = new Query();
    queryN.where = '1=1';
    queryTaskN.executeForCount(queryN, storeResultsN);
  }

  function storeResultsN(result){
    this.N = result;
    queryTaskK = new QueryTask("http://gis.datadrivendetroit.org/arcgis/rest/services/DetroitNeighborhoodMetrics/FeatureServer/0");
    queryK = new Query();
    queryK.where = '"'+this.pctileField+'" > ' + this.pctileValue;
    queryTaskN.executeForCount(queryK, storeResultsK);

  }

  function storeResultsK(results) {
        k = results;
        console.log("k:",k , "n :", this.N);
        p = k / this.N;
        console.log(p);
        P = p*100;
        console.log(P.toFixed(2)+"%");
  };

  // call attribute exemple !
  pctile("median_amount",60);

});

Answer 2

My problem here was that I was trying to call the function pctile which was not in the scope in which I was calling it.

I think this pseudo code should explain it:

//set up AMD
require([some dependencies, including query and all other ESRI stuff I need...],
function(some functions, including query and all other ESRI stuff I need...) {
    function pctile(arguments) {a function using query...};
});
//end AMD
pctile(passing arguments);

This didn't work because percentile wasn't declared in the right scope. But if I moved pctile to the scope in which I called it, I could not use query and QueryTask, because they were set up in the AMD. However, because of some other issues, I couldn't move my other code into the AMD, either.

So, the solution was to set up nested AMDs. That way my pctile function could access query and QueryTask, and it was in the right scope when I needed to call it. Like so:

//set up AMD
require([some dependencies, including query...],
function(some functions, including query...) {
    function pctile(arguments) {a function using query...};
pctile(passing arguments);
    //set up nested AMD
    require([some dependencies, including all other ESRI stuff I need...],
    function(some functions, including all other ESRI stuff I need...) {
        do something...
    });
    //end nested AMD
pctile(passing arguments);
});
//end AMD

I don't know if this is ideal, but it gets the job done.