Let's start with a context, as a context makes the whole process fun. You want to sell frozen sweets. Each frozen sweet has its variants. Generally-speaking, these variants specify a quantity, and a flavor — and some sweets come with the option of being sugar-free. The following is a screenshot of the popsicle product page as it is now.
To be fair, there could be much more variants here. I was limited to 10 SKUs when I set up my fake shop for this tutorial. Still, seeing these 8 options in a table next to 8 radio buttons is not very pretty.
What we'd aim for would be something like this:
The algorithm is super simple, and the JavaScript code needed to implement it will be easy too — easy enough.
That's it and all. Now, let's get to it.