How to load a .csv file into crossfilter with d3?

Question

I am trying to load a .csv file into crossfilter for further use it with dc.js and d3. However, if the ndx = crossfilter(data_) is not inside d3.csv(..., it does not work. Is it possible to load data using d3 inside a global/outside variable (in this case ndx)?

 var ndx;

 private method(){

        var data_;

        d3.csv("samples.csv", function(data){

            var format = d3.timeParse("%m-%y"); 

            data.forEach(function(d: any) {
                d.date = format(d.date);
            });

            data_ = d3.csvParse(data);
        });

        ndx = crossfilter(data_);
}

How can I load it into crossfilter? Am I obligated to use crossfilter inside the d3.csv(.. call?

---

Solution: I made my .csv became a .json and I loaded it 'synchronously'. Observe below.

 var ndx;

 private method(){

        var data_ = (function() {
            var json: any = null;
            $.ajax({
                'async': false,
                'global': false,
                'url': "samples.json",
                'dataType': "json",
                'success': function (data:any) {
                    json = data;
                }
            });
            return json;
        })(); 

        ndx = crossfilter(data_);
}

Observe:

'async': false

Answer 1

This happens because the callback function is executed asynchronously, once the data is returned. This means that if you put the charting code outside of the callback, you are going to get the empty array that you defined because no data has been returned yet.