Starlifter.NZ | Interstella tech intergalactic

Sticky Nav using vanilla JavaScript

Posted
June 3, 2018
Categories
Javascript

Screenshot of a sticky nav bar that uses vanilla Javascript.

I didn’t realise how easy it would be to make a sticky nav bar that uses vanilla Javascript.

This is something I’ve been wanting to learn for a long time. I was surprised how easy it is to make a sticky nav using vanilla JavaScript.

The method querySelector is used to target the navigation bar which has an ID of main, this is assigned to the variable nav. The distance between the the nav bar and the top of the window is calculated using the offsetTop property of the element.

A function named fixNav is created with an if…else statement inside it. If the distance that the page has scrolled is greater or equal to the value set in the topOfNav variable two things happen; a class of fixed-nav is added to the body tag and the height of the nav bar is added to the stop of the window to account for it coming out of the flow of the page. If the distance that the page has scrolled is less than value set in topOfNav the class is removed the padding-top is set to 0.

On the css side of things the nav bar with the newly appended class of fixed-nav is given a position of fixed and a subtle shadow.

Icecast Connected Devices Widget 📻

Posted
May 31, 2018
Categories
Javascript

Number of connected listeners widget for 8K.NZ

With all the mad knowledge and skills I’ve been learning lately I thought it’d be a good time to try writing my own thing. So I decided to have a go at writing my own widget to display how many devices are connected to the Icecast server for the online radio station I help run, 8K.NZ 📻

The live widget is here: http://8k.nz/current-listeners/
The code is up on Github here: https://github.com/starlifter-nz/icecast-device-stats

I’m going to attempt to describe what I did with the JavaScript. The Icecast server has a publicly accessible JSON object of live stats, I assigned this to a variable called endpoint. I accessed the object via a new DOM API called Fetch. This was then put in a function called blob which was then deconstucted into a constant called source. The value of the number of listeners is then assigned to the numbers variable.

Due to how the English language deals with singularity and pularity I needed to write an if statement to accommodate this. If the value of the variable number is 0, or 2 or greater, the first section of HTML is displayed inside the element with the id of noOfListeners. Otherwise if there is only 1 listener the second section of HTML is displayed.

This all gets wrapped in a getStreamStats function which is then called. The setTimeout method is then used in conjunction with a repeat method so that the getStreamStats function is run every 44 seconds. At 8K we like to have fun with numerology around the number 8 🤖

I learnt so much building what from the surface looks like a simple widget. Thanks to the follow people for their help and support:

Jeff Knaggs
charlietfl

Object and Arrays – Reference vs Copy

Posted
May 22, 2018
Categories
Javascript

Screenshot of working through the “Object and Arrays – Reference vs Copy” tutorial.

This tutorial worked through the differences between referring to a variable, array or object and making a copy that you can then manipulate without affecting the original. There were a couple key takeaways I found interesting with this exercise.

The first was that if you let one variable be assigned a value, then refer that variable to a new one and then reassign the first variable this doesn’t change the second.

Next I learnt three ways of copying an array. I think my favourite is using the spread syntax as follows:

const showHosts = ['Pinacolada Soundsystem', 'Fraserhead', 'Dave Branton', 'Dr Hitchcock'];
const eightKayMembers = [...showHosts];