DataTables

DataTables Examples

JavaScript

var element,
    result = {},
    test = [
            {"key":"main1","value":320},
            {"key":"main2","value":240},
            {"key":"front1","value":220},
            {"key":"main1","value":300},
            {"key":"main2","value":240},
            {"key":"front1","value":120},
            {"key":"front5","value":120}
         ];

for (i in test) {
    element = test[i];
    if (!result[element.key]) {
        result[element.key]=[element.value];
    } else {
        result[element.key].push(element.value);        
    }
}

console.dir(result);