Aquí es mi propia respuesta:
form.uploadDir = "temp/uploads";
form.keepExtensions = true;
form
.on('error', function(err) {
throw err;
})
.on('field', function(field, value) {
//receive form fields here
})
/* this is where the renaming happens */
.on ('fileBegin', function(name, file){
//rename the incoming file to the file's name
file.path = form.uploadDir + "/" + file.name;
})
.on('file', function(field, file) {
//On file received
})
.on('progress', function(bytesReceived, bytesExpected) {
//self.emit('progess', bytesReceived, bytesExpected)
var percent = (bytesReceived/bytesExpected * 100) | 0;
process.stdout.write('Uploading: %' + percent + '\r');
})
.on('end', function() {
});
form.parse(req);
La respuesta fue en la página GitHub del módulo ¡todo el tiempo!
'.on' me daría errores. Lo tengo para trabajar, sin embargo, con 'form.on' – Houseman