Select First Variant On Stock When Product Page Loads

[j-meel]

Hi, 

On my product page I show a message when an item is out of stock or when something is in stock.

I have enabled "continue selling when out of stock" for my Webshop. The problem is that when size "S" is sold out, the product loads saying "out of stock". Lets say size "M" is in stock I would like the product page to load with variant "M" So the message "In stock" is shown. I tried googling it but only came to this site:

https://www.slicedbread.agency/blogs/shopify/automatically-open-the-first-available-variant-using-li... 

This points me in the right direction but I would need a bit more explanation where and how to loop etc.

Hope you guys can help me out.

I'm using the Empire theme

Thanks 

[Enamhasan]

Try this
https://gist.github.com/enamhasan/de39c2a078fe47735996e9c0ccc77e48