node.js - Iterating over a mongodb cursor serially (waiting for callbacks before moving to next document) -

using mongoskin, can query this, return cursor:

mycollection.find({}, function(err, resultcursor) {       resultcursor.each(function(err, result) {        } } 

however, i'd call async functions each document, , move on next item on cursor after has called (similar eachseries structure in async.js module). e.g:

mycollection.find({}, function(err, resultcursor) {       resultcursor.each(function(err, result) {              externalasyncfunction(result, function(err) {                //externalasyncfunction completed - want move next doc             });        } }   

how this?

thanks

update:

i don't wan't use toarray() large batch operation, , results might not fit in memory in 1 go.

if don't want load of results memory using toarray, can iterate using cursor following.

mycollection.find({}, function(err, resultcursor) {   function processitem(err, item) {     if(item === null) {       return; // done!     }      externalasyncfunction(item, function(err) {       resultcursor.nextobject(processitem);     });    }    resultcursor.nextobject(processitem); }