async calls

run.js

fetchProfile(1, function(){
  console.log("Callback 1");
});
fetchProfile(2, function(){
  console.log("Callback 2");
});
fetchProfile(3, function(){
  console.log("Callback 3");
});
fetchProfile(4, function(){
  console.log("Callback 4");
});
fetchProfile(5, function(){
  console.log("Callback 5");
});
fetchProfile(6, function(){
  console.log("Callback 6");
});
fetchProfile(7, function(){
  console.log("Callback 7");
});
fetchProfile(8, function(){
  console.log("Callback 8");
});

function fetchProfile(n, callback){
  console.log("Running ", n);
  if(n === 2){
    setTimeout(function(){
      callback();
    }, 800);
  }else{
    setTimeout(function(){
      callback();
    }, 200);
  }
}


/*
Output:
  Running  1
  Running  2
  Running  3
  Running  4
  Running  5
  Running  6
  Running  7
  Running  8
  Callback 1
  Callback 3
  Callback 4
  Callback 5
  Callback 6
  Callback 7
  Callback 8
  Callback 2
*/