[Alexandroppolus]

function groupping(arr) {
    var result = [], map = Object.create(null);
	arr.forEach(function(item) {
		var group = map[item.hash];
		if (!group) {
        	group = map[item.hash] = {name: item.hash, totalBalance: 0, data: []};
			result.push(group);
		}
		group.totalBalance += item.balance;
		group.data.push(item);
    });
	return result;
}