You could do:

    Q.spread(client.keys('transaction-*'), client.keys('product-*'),  client.keys('seller-*'))
      .then(function(transKeys, productKeys, sellerKeys) {
      ...
      });

not sure if that would make things easier or not

https://github.com/kriskowal/q/wiki/API-Reference#promisespreadonfulfilled-onrejected