What is the best way to join callback functions into a single callback?

Question

Given the JavaScript code:

self.queue.now( 'test_1', function() {
    self.queue.now( 'test_2', done )
})

.. where the now fn() has a callback argument, what is the best way to combine / join the callbacks so that the code is no longer nested? Specifically, I would like to have the self.queue.now calls be on the same indentation level and when both are finished, only then, would done() be called.

Answer 1

Solution ended up leveraging async.parallel:

async.parallel( [
    function( cb ) {
        self.queue.now( 'test_1', cb )
    },
    function( cb ) {
        self.queue.now( 'test_2', cb )
    }
], done )

Although it would have been nice to not have the function( cb ) wrappers ..