NodeJS: throw er; //Unhandled 'error' event (events.js:72) when using child_process spawn method - node.js

Question

I've made an node.js app to list all .txt files from a directory recursively and, for each one, do some stuff.
Here's my app.js:
var spawn = require('child_process').spawn,
dir = spawn('dir', ['*.txt', '/b']);
dir.stdout.on('data', function (data) {
//do some stuff with each stdout line...
console.log('stdout: ' + data);
});
dir.stderr.on('data', function (data) {
//throw errors
console.log('stderr: ' + data);
});
dir.on('close', function (code) {
console.log('child process exited with code ' + code);
});
When I run node app.js via console, I get the error message below:
events.js:72
throw er; // Unhandled 'error' event
^
Error: spawn ENOENT
at errnoException (child_process.js:980:11)
at Process.ChildProcess._handle.onexit (child_process.js:771:34)
I'm using node v0.10.13 at win32 environment.
I do this way (spawn) because I want to handle stdout line by line (the exec method release entire stdout as one string).
* UPDATE *
By the way, using spawn for child_process does not guarantee that the output for cmd dir will be line by line. I've created a question for that too.

Answer 1

That happen because dir is not a executable in Windows. It's a command from the shell.
The solution for your problem is the following:
var dir = spawn('cmd', ['/c', 'dir']);
dir.stdout.on("data", function() {
// do things
})
This exact problem was here also.

Answer 2

Several things:
dir is not a real executable in windows, so node.js cannot find the program you want to run.
You didn't bind an 'error' handler to your child process and the event was turned into an exception that crashed your node instance. Do this:
dir.on('error', function (err) {
console.log('dir error', err);
});
Use fs.readdir instead. It's a standard node.js API that does the same thing.