In this article, we will go through the different data types that MongoDB supports. Let’s start with the basic types first. We can identify 6 basic types: null, boolean, numeric, string, array and object. If you are familiar with JSON, the representation of data in MongoDB will look familiar. JSON allows you to represent data by using key/value pairs and use those six basic types.
Continue reading Data types in MongoDB

Read more

I recently found out that it’s very easy to get lost in the daily challenges of being a freelancer. The lack of real structure around yourself can make it difficult to distinguish code written for work and code written for play. It has become a bit difficult for me to say stop, my work for today is done, without feeling a little guilty about something. It can be how productive I was during the day, or I perceived the quality of the code I wrote.

Those things can be solved by a different mindset and a strong discipline. Work starts and stops at a certain predefined hour, except emergencies. Whatever code I write after or before those hours, it’s playtime.

The other problem I need to solve is, what do I do in my playtime? I like to learn new things, but I also need to become better. Learning something new is quite different from working on your fundamentals. So I chose two courses of actions in my case:

  • Learn a new language: I chose C#.
  • Choose a engaging side project to work on.

There is not really anything crazy behind the C# choice. I love to learn using Treehouse and they have a course on this language, so that’s really all there is to it. It’s also something quite different from Javascript, which is the language I mostly use. I believe it’s always important to explore new things.

Here comes the real problem: what side project to choose? I thought about this quite a bit. I still haven’t found anything serious yet, only a few ideas. But I think I can list a few things that a side project should have in order to become interesting:

  • Be personal. Solve one of your problems. If the project is something you can relate to, it will be easier to motivate yourself to work on it and/or make it better.
  • Be in the realm of possible. This one is about your current skills as a developer and also about being realistic. I love video games, but I don’t believe trying to make the next World of Warcraft could be considered a good side-project.
  • Have a future. It can scale. If more users get to use your project, that would not be a problem.
  • Be open source. Two reasons: you increase the chance of having other people use your project. And it could become easier to find help if you get stuck at one point. It would most likely help with the scalable issue.

So, that is what I think a side project should have to make me work on it on a regular basis. I decided that I wouldn’t start a side project until I become quite sure that I would spend some time on it and be proud of it in the end.

Let me know if you think a side project should have different attributes. How do you choose your side projects?

As always, feel free to share and comment.
Have a nice day!

Read more


The #100DaysOfCode is a challenge that aims at making coding a habit. The concept is very simple. Every day, you spend at least an hour doing non-work related programming. The challenge also insists on building projects, and not spending your time doing only tutorials or following courses. You must put what you learned in practice doing real projects. The projects are totally up to you of course, depending on your current skills and/or needs.

You can find more information about the #100DaysOfCode on Alexander Kallaway’s blog post.

The most important thing, in my opinion, is not the habit in itself, though it is very important. The crucial thing to me is being accountable. Hundreds of people are taking this challenge. You have the knowledge that you are not alone. You are also committing to tweet your progress and encourage at least two people each day. There is a level of accountability and connectivity with other people that just make the whole thing so much more appealing to me, and therefore, I feel confident I will be able to do it.

What to build?

That is the bit question that I had. I finished the FreeCodeCamp curriculum, all three certificates. So, I won’t be re-building any of those projects. In my opinion, in order to succeed, the projects I will choose must follow a few rules:

  • Must not take too much time to realise (the goal is to create several projects in that timeframe of 100 days)
  • Must be challenging, but not impossible. I’m not the best developer out there, so I need to choose projects I an actually do. In the mean time, the goal is to push myself, I must choose something outside of my comfort zone.
  • Must be something I would like to do. There are billions of different things I can code, but not every single one will be appealing to me. This is outside of work. **Having fun **is the number one thing I’ll be worried about.

Every single project I will choose to do will have to follow those three rules.

The brainstorm (!!!)

I spent a little bit of time thinking about this, and I cam up with this, so far:

  • War (Card Game)
  • Make a Diary application
  • Make an app using the NASA’s API
  • Belote (French Card Game)
  • A real-time application (
  • Something with Bots ?

Here are 6 different projects that I came up with. As you can see, it is still very vague. I only researched the first one a bit deeper (War). In the holidays, I played a lot of card games with my family. That was amazing and this is why I put two cards game in there. The application is kinda related to my work, but I always enjoyed working with real-time technologies. The rest are just the scratch your own itch type of application.

Will I be able to do all of this in 100 days? Doesn’t matter. The goal is to build an habit of coding every day. The goal is to make sure that you are use to be outside your comfort zone and learn every day.

In each of theses applications I want to build, there are things I don’t have much experience with. The animations that will be required in the cards games for example, never used that before.

So, this is it! I’m personally starting tomorrow (January 3rd). I look forward to see any of you on this path.

As always, feel free to comment and share.
Have a nice day!

Read more


I recently started to work with a company as a freelancer. As I got access to the source code, I had the chance to look around at what technologies were used and the particular syntax that the software was written into. The software uses for most of the communication client-server. But, as I was looking at the packages used and the code, one of those packages was socketio-file-upload. With this blog post, I’ll try out this package in order to understand better what it is supposed to do. Let’s jump into it!

What is it?

Here is the description we can read from the github link I gave you in the introduction.

This module provides functionality to upload files from a browser to a Node.JS server that runs Socket.IO. Throughout the process, if their browser supports WebSockets, the user will not submit a single HTTP request. Supports Socket.IO 0.9 and 1.0.

The intended audience are single-page web apps, but other types of Node.JS projects may benefit from this library.

Since version 0.4, this module also supports monitoring file upload progress.

Simply put, you can upload files from the client to the server using sockets. I upload a file, without using AJAX or any HTTP requests and it will be saved by the server, in a directory of my choice. Let’s see that!

Begin by create a new directory, and run npm init

Accept all the defaults and then run:

npm install --save socketio-file-upload express pug

We will connect the router of the socketio-file-upload to express later.

Let’s create a file called server.js


const express = require('express');
const app = express();
const httpServer = require('http').Server(app);
const path = require('path');
const siofu = require('socketio-file-upload');
const socketServer = require('')(httpServer);

app.set('view engine', 'pug');
app.set('views', path.join(__dirname, '/public/views'));
app.use(express.static(path.join(__dirname, '/public')));

app.get('/', (req, res) => {

socketServer.on('connection', socket => {
    console.log('Socket connected');
    socket.emit('data', 'Hello World');
    const uploader = new siofu();
    uploader.dir = path.join(__dirname, '/files');


Ok, let me explain a little but this code. Most of it is setting a server with express and and http server. If you don’t know how to do this, I wrote a blog post on getting started with

After all this setup, you can direct your attention to the socketServer connection. You can see that we instantiate a new SocketIo-file-upload instance(named uploader). Then, we tell this instance where we want the file to be upload. In this case, I want my files to go to the /files directory. Finally, this instance needs to listen to the socket that just connected.

Note: Socketio-file-upload will NOT create the directory for you if it doesn’t exist. It will throw an error instead.

That is all we need for the back-end. Let’s code our front-end now. We will use several methods from the socketio-file-upload package. First, in your public/views directory, create a file called index.pug :


h1 Hello Index
button#file_button ClickHere

Nothing crazy here, a file input and a button to play around with a method we’ll see in our js file. Then, we link to our 3 different scripts. One for the library, one for the socketio-file-upload library (both are in our node_modules directory) and one for our custom script called main.js. Let’s see our custom main.js:

//Connection to the socket library
const socket = io();

//This is some classic event listening
socket.on('data', data => {

//Here is our socketio-file-upload code
const uploader = new SocketIOFileUpload(socket);


uploader.addEventListener('start', (event)=> {
    event.file.meta.extension = 'csv';

document.getElementById('file_button').addEventListener('click', uploader.prompt, false);

Ok, here is how we do things. We create a new SocketIOFileUpload instance, with our socket as a parameter. We can use the listenOnInput method on our input file. As you can see, we pass the DOM element that we want to listen to. When we will choose a file, we will trigger this event.

When we do that, we will go back to our server.js file. Our socketio-file-upload instance on the back-end will receive this file (remember that it listens to our socket). Once it receives this file, it will store it in the directory that we specified.

I added some custom code on the start event of the instance. You can write on the event.file object for example. Here, I decided to add extension : 'csv' to the meta object. You can imagine that the possibilities are infinite when it comes to playing with the object.

Lastly, you might have seen on the index.pug that I added a button. The last two lines on main.js adds an event listener to a click event on this button. I use the instance.prompt method (instance being here uploader). This will trigger the opening of the same window you would have on a input file.

That’s it! Those are just a few methods available on the socketio-file-upload package. To learn more, you can visit the very good github socketio-file-upload page. You can peak at the documentation to learn more.

Note: you may wonder what is the difference between this package and the streams package. The stream package will be user to read files. We create a stream to read the contents of the file. With this package, we do not read it, we store it in our files directory (in our case). We could of course read the file with a socket stream and then upload it. Or upload it, then read it with a stream. Both those packages could be very complementary in my opinion.

Feel free to share and comment!
Have a nice day!

Read more


Yesterday, I received my Pavlok. If you are not familiar with it, Pavlok is a device that is focused on changing your habits with the help of electrical stimulus. The most effective way to use it is to zap yourself when you are doing a bad habit. For example, every time I bit my nails, ZAP!

The Pavlok system tries to break the cue-routine-reward path by making the reward not as pleasant. If your habit is rewarded by an electric shock, your brain will associate this habit with pain or discomfort. Because we are creatures of pleasure, we will most likely stop doing this habit.

But, as a part of the Internet of Things trend, Pavlok also allows you to customise its use and add some tweaks. For example, there is a Chrome extension available. If I spend too much time on Twitter, I will get zapped. I also linked my Pavlok with RescueTime. This way, I get notified when I’m being productive (vibrating), when I could do better (beeping) and when I’m being baaaaaad (ZAAAAP !).

Ok, so this is great. But the even cooler part is this: Pavlok has a developer API that allows us to interact with our devices through code. This is what this post is about: getting started with the Pavlok developer API.

Getting started

We will use Node.JS to achieve this. First things first, we need to register our application, the same way we would do with Twitter in order to use its API. To do this, visit this page. Enter the name of your app and for the callback URL, just enter http://localhost:3000/auth/pavlok/result .

Great, now our app is registered. You will get a Client ID and a Client Secret. We will need them in our app.

Create a file, let’s call it test.js.

First, run npm init. Select the defaults and then run npm install --save pavlok-beta-api-login

Let’s write our code!

const pavlok = require('pavlok-beta-api-login');
const ClientID = "YOUR_CLIENT_ID";
const Secret = "YOUR_SECRET_ID";

// Init your device
pavlok.init(ClientID, Secret, {
        verbose: true,
        port: 3000

pavlok.login( (result, code) => {
        console.log('Code is', code);

// Your device will beep

//Your device will vibrate

//This is a pattern
// (Beep & Vibrate) * 3
"pattern": ['beep', 'vibrate'],
"count": 3

And that is all we need!
Run node test.js and your device will respond to the stimuli. You Pavlok application will also receive notifications with the name of your app! Awesome!!

Note that the code will be different if you host your application. On local, this code will be fine. But if you need to host it, you’ll need to change a few things. You can check the npm pavlok wiki page to get more information on how to do this.
You can get more information about the device on the Pavlok website and more information on the Developer API can be found on the Pavlok Developer API

I’ll post more informations as I keep playing with it. But this is enough to get you started. Have fun!

Feel free to comment and share!
Have a nice day!

Read more


In this article, we will see very simply how to use namespaces with Namespaces allow us to group sockets based the page the user visits. In our example, we will use three different groups. One group will contain the sockets in the index page ‘/’, another in the ‘/products’ page and another one in the ‘/contact’ page.

First things first, create a directory that will hold our project. Then, run npm init. Accept the defaults and then install our needed dependencies with :

npm install --save express 

Ok, now create 4 files, server.js, index.html, products.html, contact.html.

Let’s start with our server.js:

const express = require('express');
const http = require('http');

const app = express();
const server = http.Server(app);
const ioServer = require('')(server);

const indexUsers = ioServer.of('/');
const productsUsers = ioServer.of('/products');
const contactUsers = ioServer.of('/contact');

// Express file rendering
app.get('/', (req,res)=> {
    res.sendFile(__dirname + '/index.html');

app.get('/products', (req,res)=> {
    res.sendFile(__dirname + '/products.html');

app.get('/contact', (req,res)=> {
    res.sendFile(__dirname + '/contact.html');

// logic

//Index page sockets
indexUsers.on('connection', socket => {
    socket.emit('connectionMessage', 'Welcome to the index page');

//Products page sockets
productsUsers.on('connection', socket => {
    socket.emit('connectionMessage', 'Welcome to the products page');

//Contact page sockets
contactUsers.on('connection', socket=> {
    socket.emit('connectionMessage', 'Welcome to the contact page');


Quick explanation: We begin by initialising our server like usual. We use express to server our three html files. Nothing crazy so far. But notice that we define three variables with the of() method on our ioServer. This tells that depending on the connection made in the front-end, we will group sockets differently. We are then able to use the emit event (or the on event) on those namespaces like any other socket. Let’s see how our three html files will look.

They all look very similar, but I wanted to make sure that everything was clear.


<!DOCTYPE html>
        <title>Index Page</title>
        <script src=""></script>
        <h1>Welcome to the Index Page</h1>
        <h3 id="message"></h3>
            const socket = io('/');

            socket.on('connectionMessage', message => {
                document.getElementById('message').innerHTML = message;


<!DOCTYPE html>
        <title>Products Page</title>
        <script src=""></script>
        <h1>Welcome to the Products Page</h1>
        <h3 id="message"></h3>
        const socket = io('/products');

        socket.on('connectionMessage', message => {
            document.getElementById('message').innerHTML = message;


<!DOCTYPE html>
        <title>Contact Page</title>
        <script src=""></script>
        <h1>Welcome to the Contact Page</h1>
        <h3 id="message"></h3>
            const socket = io('/contact');

            socket.on('connectionMessage', message => {
                document.getElementById('message').innerHTML = message;

Alright, the structure of those files is exactly the same. Standard html, with a script for the CDN. Then, two headers, a h1 that tells us on which page we are on, and an h3 with the id of message. In our script, the socket reacts to the connectionMessage event by putting the message in our h3.

Can you spot the difference between those files?
The definition of our socket is different. The argument in our io() function is what creates the namespace. In combination with the variables definition we did in server.js, we created separated groups of sockets that can emit and respond to socket events independently from one another. Pretty cool huh?

And that’s it! This is a very simple beginning, just to make you understand how this thing works. Of course, this opens a lot of different possibilities. Go ahead and experiment!

As always, feel free to comment or share.

Have a nice day!

Read more