I am playing with some JSON type of data, and need to do some reports, in particular a "group by count" query, so here is what I came up with:
var groupByCount = function(list, name){
var groups = {};
list.forEach(function(d){
if(groups[d[name]]){
groups[d[name]]++;
} else {
groups[d[name]] = 1;
}
});
return groups;
};
(I am using the '.forEach' method available in node.js, but this could be replaced with a regular loop and used on the client.