source: imaps-frontend/node_modules/nano-css/addon/nesting.js

'use strict';

exports.addon = function (renderer) {
    renderer.selector = function (parentSelectors, selector) {
        var parents = parentSelectors.split(',');
        var result = [];
        var selectors = selector.split(',');
        var len1 = parents.length;
        var len2 = selectors.length;
        var i, j, sel, pos, parent, replacedSelector;

        for (i = 0; i < len2; i++) {
            sel = selectors[i];
            pos = sel.indexOf('&');

            if (pos > -1) {
                for (j = 0; j < len1; j++) {
                    parent = parents[j];
                    replacedSelector = sel.replace(/&/g, parent);
                    result.push(replacedSelector);
                }
            } else {
                for (j = 0; j < len1; j++) {
                    parent = parents[j];

                    if (parent) {
                        result.push(parent + ' ' + sel);
                    } else {
                        result.push(sel);
                    }
                }
            }
        }

        return result.join(',');
    };
};