So you’re converting a value to a boolean, then inverting it, then inverting it again. Take a look at the three examples below that mean the same thing starting with the double exclamation mark.
// Really Confusing: site.enable = !!webId; // Less Confusing: site.enable = (webId != 0) ? true : false; // Easiest to understand in my opinion: site.enable = (webId != 0);