parallel example

parallel.js

var timer = require('timers')
  , result = 0
  , iter = 0;

var A = function(){
  var B = function(callback){
    callback(50);
  }
  var C = function(callback){
    callback(25);
  }
  B(execute);
  C(execute);
}

function execute(data){
  result += data;
  if (!iter){
    iter++
    return
  }
  console.log(result);
}
A();