_.js

$scope.subscriptions = _.map(_.sortBy(_.filter(subscriptions, function(sub) {
              return sub.transactions && sub.transactions.length;
          }), function(sub) {
              return _.last(sub.transactions).created_at;
          }), function(sub) {
              var last_transaction = _.last(sub.transactions),
                totals = _.reduce(sub.transactions, function (memo, t) {
                    return memo + t.amount/100.0;
                }, 0);

              return {
                  email: sub.user.email,
                  last_transaction_date: last_transaction.created_at,
                  last_transaction_amount: last_transaction.amount/100.0,
                  total_transactions: sub.transactions.length,
                  transactions_total: totals,
                  will_cancel: sub.willCancelAfterPeriod
              };
          }).reverse();