cannot print all elements in collection although count is positive - node.js

Question

I can get positive count of elements in collection ...
var collection;
collection = db.collection("allCodes");
collection.count(function(err, count) {
if (err) {
throw err;
}
console.log("There are " + count + " records.");
});
... with output:
Connected to Database ok
There are 354 records.
... but can not get elements in this collection:
collection.find().each(function(err, doc) {
if (err) {
throw err;
}
console.log("each doc");
console.log(doc);
});
... it prints nothing. I am new in mongodb. So what I do wrong? I want to print all elements in allCodes collection.
Update: all code that inserts data then gets count and then tries to fetch data itself, but nothing comes out.
var MongoClient, collection;
MongoClient = require("mongodb").MongoClient;
var objectToInsert = [{
'a': 1
}, {
'a': 2
}, {
'b': 3
}]
MongoClient.connect("mongodb://127.0.0.1:27017/test", function(err, db) {
console.log("Connected to Database");
collection = db.collection("test2");
// clear collection -------------------------------
collection.remove(function(err, result) {
// insert ------------------------------------
collection.insert(objectToInsert, function(docs) {
// count - ok -----------------------------------
collection.count(function(err, count) {
console.log("Count: " + count);
// find - fail - no objects printed -----------------------
collection.find().toArray(function(err, docs) {
console.log("Printing docs from Array");
docs.forEach(function(doc) {
console.log("Doc from array");
console.log(doc);
});
});
db.close();
});
});
});
});
It has output:
Connected to Database
Count: 3
So why I have only count. Where is my data?

Answer 1

You're closing your connection to the database before the find gets a chance to complete.
Move the db.close() call inside the callback of toArray like this:
collection.find().toArray(function(err, docs) {
console.log("Printing docs from Array");
docs.forEach(function(doc) {
console.log("Doc from array");
console.log(doc);
});
db.close();
});

Answer 2

Disclaimer: I am not familiar with node.js at all.
From the example in the documentation, it seems that you are required to create a cursor object first and only afterwards iterate over the results. I'm not sure what considerations there are for chaining commands.
var cursor = collection.find();
// Execute the each command, triggers for each document
cursor.each( function( err, item ) {
console.log( "each doc" );
});