group items of list by proprety value js
function groupBy(collection, property) { var i = 0, val, index, values = [], result = []; for (; i < collection.length; i++) { val = collection[i][property]; index = values.indexOf(val); if (index > -1) result[index].push(collection[i]); else { values.push(val); result.push([collection[i]]); } } return result; } var obj = groupBy(list, "group"); //https://stackoverflow.com/questions/21776389/javascript-object-grouping
