gistfile1.txt

function doThingsWithItems(callback) {
  var items = ["foo", "bar", "baz"];
  var remaining = items.length + 1;

  items.forEach(function(item) {
     doSomethingErrorProne(function() {
       remaining -= 1;
       if (remaining == 0) {
         callback();
       }
    })
    
  });
}