How to find a file.csv/.json inside of a folder (by code) and use it as datasource

I have a folder named “static” which contains another folder called “data” where I uploaded several .csv and .json files, and I want to know how to access those files in order to use them as data source for my webdatarocks table.
I tried with: ./static/data/test.csv
                   /static/data/test.csv
                  static/data/test.csv
and none of those seem to be working, because it throws an error saying:
Unable to open file static/data/test.csv

It seems that this file doesn’t exist or ‘Access-Control-Allow-Origin’ header is absent in the resource requested.

let pivote = new WebDataRocks({
        container: "#wdr-component",
        toolbar: true,
        report: {
            dataSource: {
                filename:  //here
                fieldSeparator: ","
            },            
             slice: objReporte.slice,
             grid: objReporte.grid
}    
});