A simple async NodeJS example

anotherExample.js

var async = require("async");

function a(callback) {
   setTimeout(function() {
      console.log('a');
      callback();
   }, 5000);
}

function b(callback) {
   console.log('b');
   callback();
}

function done() {
   console.log('all done!');
}

async.parallel([
    a,
    b
], function(err, results) {
    done()
});

asyncNodeJSExample.js

async = require('async');

//array to hold our tasks
var asyncTasks = [];

function a(callback) {
   console.log('called function a!');
   callback();
};

function b(callback) {
   console.log('called function b!');
   callback();
};

function done() {
   console.log('done!');
};

//add tasks to the queue
asyncTasks.push(a);
asyncTasks.push(b);

async.parallel(asyncTasks, function() {
   //do something once tasks are finished
   done();
});

moreComplicatedAsyncExample.js

async = require('async');

//import the ad connection logic
var ad = require('./ad.js');

//lookup an account
var sAMAccountName = 'myuser';

//array to hold our tasks
var asyncTasks = [];

function findUser(callback) {
   ad.findUser(sAMAccountName, function(err, user) {
      if (err) {
         callback(err);
         return;
      }
 
      if (! user) {
         var message = 'User: ' + sAMAccountName + ' not found.';
      } else {
         var message = user.dn;
         //console.log(JSON.stringify(user));
      }
      callback(message);
   });
};

function b(callback) {
   console.log('called function b!');
   callback();
};

function done(data) {
   console.log(data);
};

//add tasks to the queue
asyncTasks.push(findUser);
asyncTasks.push(b);

async.parallel(asyncTasks, function(data) {
   //do something once tasks are finished
   done(data);
});