Magento 2: Extract Currently Selected Product ID or SKU on Product Page

Rian managed to dig up most of the data embedded in a Magento 2 product listing page that would let a programmer extract the Product ID of the currently selected product on a configurable product page. I threw together this quick RequireJS program that shows how you might extract the actual ID.

//program to extract the currently selected ID on the product page
//testing vs. the luma theme, changes to `div.swatch-attribute`
//or `[data-role=swatch-options]` will break this

//found_ids is an array because its theoretically possible if
//other parts of Magento are misbehaving multiple IDs may match
requirejs(['jquery','underscore'], function(jQuery,_){
    var selected_options = {};
    jQuery('div.swatch-attribute').each(function(k,v){
        var attribute_id    = jQuery(v).attr('attribute-id');
        var option_selected = jQuery(v).attr('option-selected');
        //console.log(attribute_id, option_selected);
        if(!attribute_id || !option_selected){ return;}
        selected_options[attribute_id] = option_selected;
    });

    var product_id_index = jQuery('[data-role=swatch-options]').data('mageSwatchRenderer').options.jsonConfig.index;
    var found_ids = [];
    jQuery.each(product_id_index, function(product_id,attributes){
        var productIsSelected = function(attributes, selected_options){
            return _.isEqual(attributes, selected_options);
        }
        if(productIsSelected(attributes, selected_options)){
            found_ids.push(product_id);
        } 
    });
    console.log(found_ids);
});