less.js/lib/less-browser/utils.js

module.exports = {
    extractId: function(href) {
        return href.replace(/^[a-z-]+:\/+?[^\/]+/, '' )  // Remove protocol & domain
            .replace(/^\//,                 '' )  // Remove root /
            .replace(/\.[a-zA-Z]+$/,        '' )  // Remove simple extension
            .replace(/[^\.\w-]+/g,          '-')  // Replace illegal characters
            .replace(/\./g,                 ':'); // Replace dots with colons(for valid id)
    },
    addDataAttr: function(options, tag) {
        for (var opt in tag.dataset) {
            if (tag.dataset.hasOwnProperty(opt)) {
                if (opt === "env" || opt === "dumpLineNumbers" || opt === "rootpath" || opt === "errorReporting") {
                    options[opt] = tag.dataset[opt];
                } else {
                    options[opt] = JSON.parse(tag.dataset[opt]);
                }
            }
        }
    }
};