Wednesday, 10 January 2018

Editing command-line JavaScript, using Atom in Ubuntu

I've been doing a lot of JavaScript recently. It would have been too painful to render through the browser each time. So I set up an environment to do this within the Atom text editor. I use Ubuntu, although I'm sure the following instructions can be easily adapted to lesser operating systems.

Install nodejs
curl -sL | sudo -E bash -
sudo apt-get install -y nodejs

Test this has worked by typing
node --version

Install Atom
sudo add-apt-repository ppa:webupd8team/atom
sudo apt update; sudo apt install atom

Add the terminal plugin to atom
Within atom type ctrl+, to get the settings window.
Click on install.
Type 'terminal'.
Now you will get a list of all terminal plugins for atom. I chose 'platformio-ide-terminal' and clicked the 'Install' button.
Restart atom.

Use the terminal within atom on your JavaScript
Open a directory containing your JavaScript. I suggest using the 'Add Project Folder...' option from the 'File' menu.
Let's imagine you have a directory such as /home/jimmy/js
If you haven't already, create a file such as 'hello.js'
Inside 'hello.js' add the line:
console.log('Hello world!');
Save the file.
Now at the bottom left-corner of Atom you will see a '+' symbol. Click the '+' and you will see a terminal window open in your chosen directory.
Click in the terminal window:
node hello.js
Hey presto!

Passing JavaScript arrays by reference and valuies

By default JavaScript arrays are passed by reference. See the code below. Notice that when a value in the 'firstArray' is changed, the corresponding value in 'secondArray' is also changed.

var firstArray = ['first','second','third'];
var secondArray = firstArray;

firstArray[1] = 'second most';

for (var i = 0; i < firstArray.length; i++)

/* Output
second most


To overcome this issue you need to use the 'slice' method. This will pass the 'firstArray' to the 'secondArray' by value. See, in the output, that although a value in the 'firstArray' has changed, this hasn't affected the values within the 'secondArray'.

var firstArray = ['first','second','third'];
var secondArray = firstArray.slice();

firstArray[1] = 'second most';

for (var i = 0; i < firstArray.length; i++)

/* Output


Wednesday, 3 January 2018

Fast lightweight web development on an old laptop

I was given an old laptop. It's quite handy for doing a little development when it comes into my head. Below I explain how I set it up.


The laptop has a 32-bit architecture so I downloaded Lubuntu from and replaced the slow Microsoft Windows installation.
There was one downside to this. Since Microsoft bought Skype, they have stopped supporting it's 32-bit version. Not so much of a problem for me as I have another laptop I use for more serious work, but worth noting.

PHP & Web Server

I installed PHP, but not the rest of the LAMP stack. PHP comes with a lightweight server which you can run from your working directory from the command line with the cli call of:
php -S localhost:8000
After doing that, just open up your favourite web browser and use the address http://localhost:8000


CSS has become a bit cumbersome now. I use Sass to make the process of producing stylesheets a little easier.
To install this on Lubuntu use:
sudo apt install ruby-sass
Once the install has completed you're ready to use it. First, your terminal change to the directory of your app e.g.
cd /home/mick/htmlstuff/myapp
You'll need at least 2 files for Sass. In this example we'll use custom.scss (the one we'll be editing) and custom.css (the output file which is referred to by your HTML page). Then you want to put a watch on custom.scss to produce custom.css. This again is done from the terminal with the line:
sass --watch custom.scss:custom.css
Now every time you update and save custom.scss, custom.css will be updated.


I now use Atom as my editor. To install it on Lubuntu, first add the PPA thus:
sudo add-apt-repository ppa:webupd8team/atom
Then do an update and the install through:
sudo apt update; sudo apt install atom
I had a graphic problem with mine at first. It kept flashing. To remedy this I changed the command of my Atom launcher to:
/opt/atom/atom --disable-gpu
Once Atom has been installed successfully it's time to add a few extensions. I recommend the following:
  • browser-plus - This will open up a browser inside the editor and will display changes your project live, on save.
  • file-icons - This provides more informative icons for the various files within your project.
  • platformio-atom-ide-terminal - This will open up a terminal inside the editor. It's quite useful because some commands, such as the sass one above provide you with error messages.
  • remote-sync - This will allow you to edit remote files through ftp etc. It's also particularly good because you can list all the files which shouldn't be synced.