IndexedDB using YDN-DB: What is the most efficient way to retrieve the highest Primary Key value?

While building an offline app using YDN-DB wrapper for IndexedDB, I now need to query any object store for the highest Integer primary key value in the store. By extension, I can then predict and use the next autoIncrement number, even before running the next INSERT. Presently I can think of the following approach:

db.values('store_name').done(function (recordset) {
   //run through the key/value pairs in recordset until I arrive at the 
         highest value.
});

Or perhaps:

db.from('store_name').select('primary_key').order('primary_key', true).list(1)
.done(function(value) {
  //use value for some task;
});

Is there a more efficient way? And while we're on it, the "primary_key" argument specified in .order('primary_key', true) seems superfluous to me, since this ordering would normally be by primary key. If that is right, what's the syntax to skip it?

Thanks.

EDIT:

While waiting, I realized that, in fact, with the .order('primary_key', true), the second parameter of true(==reverse) wast totally ignored by the query engine. But the below form came to the rescue:

db.from('store_name').select('primary_key').reverse().list(1)
    .done(function(highest){
        console.log(highest);

});

While this seems to be a little sleeker, I still crave an endorsement from the 'profs'.

Thank you.

Solution

This is very common operation. I will use

db.keys('store_name', null, 1, 0, true)

Using query module db.from is wrapper to above method. Sorry for regression on order ignoring direction. I will fix. Thanks for reporting.