JavaScript SUM and GROUP BY of JSON data

Question

This is my first attempt at doing JavaScript with some JSON data objects and need some advice on the proper way to attain my goal.

Some server-side code actually gen

Answer 1

Given the dataString above, the below code seems to work. It goes through each object; if the category exists in the groupedObjects array, its hits and bytes are added to the existing object. Otherwise, it is considered new and added to the groupedObjects array.

This solution makes use of underscore.js and jQuery

Here's a jsfiddle demo: http://jsfiddle.net/R3p4c/2/

var objects = $.parseJSON(dataString);
var categories = new Array();
var groupedObjects = new Array();
var i = 0;

_.each(objects,function(obj){
    var existingObj;
    if($.inArray(obj.category,categories) >= 0) {
        existingObj = _.find(objects,function(o){return o.category === obj.category; });
        existingObj.hits += obj.hits;
        existingObj.bytes += obj.bytes;
    } else {
        groupedObjects[i] = obj;
        categories[i] = obj.category;
        i++;
  }
});

groupedObjects = _.sortBy(groupedObjects,function(obj){ return obj.bytes; }).reverse();