Executing asynchronous calls in a synchronous manner

Question

I've been trying to wrap my head around this issue for the last hours but can't figure it out. I guess I still have to get used to the functional programming style ;)

I wrote a recursive function that traverses through a directory structure and does things to certain files. This functions uses the asynchronous IO methods. Now I want to perform some action when this whole traversing is done.

How would I make sure that this action is performed after all parse calls have been performed but still use the asynchronous IO functions?

var fs = require('fs'),     path = require('path');  function parse(dir) {     fs.readdir(dir, function (err, files) {         if (err) {             console.error(err);         } else {                             // f = filename, p = path             var each = function (f, p) {                 return function (err, stats) {                     if (err) {                         console.error(err);                     } else {                         if (stats.isDirectory()) {                             parse(p);                         } else if (stats.isFile()) {                             // do some stuff                         }                     }                 };             };              var i;             for (i = 0; i < files.length; i++) {                 var f = files[i];                 var p = path.join(dir, f);                 fs.stat(p, each(f, p));             }         }     }); }  parse('.');  // do some stuff here when async parse completely finished 

Answer 1

Look for Step module. It can chain asynchronous functions calls and pass results from one to another.