I am loading a JSON data into the datatable, and I would like to interpret the values, for example, count of IDs where the status=“installed”, and so on.
There are multiple way. You can use eachRow to iterate through grid for example
http://docs.webix.com/api__ui.datatable_eachrow.html
var count = 0;
$$("dtable").eachRow(function(){
if (this.getItem(id).status == 'installed') count++;
});