Async Iterator Snippet

iterator_async.js

var arr = [1, 2, 3, 4, 5, 6, 7]
  , results = []
  , len = arr.length

;(function iterator(i) {
  if (i >= len) {
    callback(null, results)
  } else {
    async_work(function(err, res) {
      if (err) {
        callback(err)
      } else {
        results.push(res)
        iterator(i + 1)
      }
    })
  }
})(0)