var fn = function()

in lib/is.js [249:262]


    var fn = function (data, opts) {
        if (!util.isString(data)) {
            return false;
        }

        if (options.re) {
            options.re.lastIndex = 0;
            if (!options.re.test(data)) {
                return false;
            }
        }

        return options.after ? options.after(data, opts || {}) : true;
    };