nodejs.express.Q.js

var sys = require('sys')

function Queue() {
  this.arr = []
}

Queue.prototype.push = function(fn) {
  this.arr.push(fn)
}

Queue.prototype.run = function() {
  var self = this
  if (this.arr.length)
    this.arr.shift()(function(){
      self.run()
    })
}

queue = new Queue

queue.push(function(next){
  setTimeout(function(){
    sys.puts('1')
    next()
  }, 1000)  
})

queue.push(function(next){
  setTimeout(function(){
    sys.puts('2')
    next()
  }, 200)  
})

queue.push(function(next){
  setTimeout(function(){
    sys.puts('3')
    next()
  }, 100)  
})

queue.push(function(next){
  setTimeout(function(){
    sys.puts('4')
    next()
  }, 300)  
})

queue.run()