gistfile1.txt

return [200, headers:{}, body:{
   forEach: function(write){
      var promise = new Promise;
      someEventEmitter.addListener("data", function(data){
         write(data);
      }
      someEventEmitter.addListener("complete", function(){
         promise.resolve();
      }
      return promise;
   }
 };
 
// or an example of leveraging promise chaining
return [200, headers:{}, body:{
   forEach: function(write){
      return someLazyAsyncArray.forEach(function(item){
         write(JSON.stringify(item));
      });
   }
 };