programming async trick.

answer.js

//Question:
  // Environment: NodeJS

// Lets suppose that you have a collection of items, and your function must persist all items using the
 //database.insert(item, callback ) function. When you finish the task, you should call the callback function. 
// If one item raise a error, the callback(err) must be called and never call the callback anymore.


function noop() {}

function saveBulk(items, callback) {
  var completed = 0;
  items.forEach(function(item) {
    database.insert(item, function(err) {
      if (err) {
	callback(err);
	callback = noop;
	return;
      }

      if (++completed == items.length)
	callback(null);
    });
  }); 
}

saveBulk([ {name:"thiago"}, {name: "r42"}, { name: "rulio"} , { name: "nodejs"} ], function(err) {
  console.log("Ok");
});

question.js

//Question:
  // Environment: NodeJS

// Lets suppose that you have a collection of items, and your function must persist all items using the
 //database.insert(item, callback ) function. When you finish the task, you should call the callback function. 
// If one item raise a error, the callback(err) must be called and never call the callback anymore.

  
function saveBulk(items, callback) {
   // Your code here
}

 saveBulk([ {name:"thiago"}, {name: "r42"}, { name: "rulio"} , { name: "nodejs"} ], function(err) {
   console.log("Ok");
 });