Correct me if I'm wrong but it doesn't lead to layout shift if you attach that "has-js" or remove the "no-js" class from the document if the script is in the <head> without async/defer or so it's executed before the body and CSS are even rendered. Doing this is useful for styling other <noscript> other related situations as well.
Using a checkbox is a hack in that you are using a <input> but not as a part of a form. The vestigial element gets rendered in all sorts of contexts where the CSS isn't downloaded or used. And even still, to get the ARIA you need for this menu to be accessible, you'll need to invoke JavaScript for to set the element attribute states anyhow. The anchor is a hack as well because it's not being used to link to any ID on in the document.
I also just gave this author's site a go. If I checked the box by using the keyboard, I can't close it with the mouse (or vise versa). It's a little funny as well since the menu items fit on the site without needing to make a menu button and at a small enough breakpoints it doesn't even break the items into multiple lines. Perhaps this is the anchor that's getting hit in the other case. ...And if the author had concerns about JavaScript, they would have done the syntax highlighting on the server side as well.
I wish there was an existing element for developers to just use though since it's a common pattern at this point. Then we wouldn't need to use said hacks or involve JavaScript that many users disable by default for security/privacy.
Using a checkbox is a hack in that you are using a <input> but not as a part of a form. The vestigial element gets rendered in all sorts of contexts where the CSS isn't downloaded or used. And even still, to get the ARIA you need for this menu to be accessible, you'll need to invoke JavaScript for to set the element attribute states anyhow. The anchor is a hack as well because it's not being used to link to any ID on in the document.
I also just gave this author's site a go. If I checked the box by using the keyboard, I can't close it with the mouse (or vise versa). It's a little funny as well since the menu items fit on the site without needing to make a menu button and at a small enough breakpoints it doesn't even break the items into multiple lines. Perhaps this is the anchor that's getting hit in the other case. ...And if the author had concerns about JavaScript, they would have done the syntax highlighting on the server side as well.
I wish there was an existing element for developers to just use though since it's a common pattern at this point. Then we wouldn't need to use said hacks or involve JavaScript that many users disable by default for security/privacy.