Function isEmpty

tests/spec/s-xregexp.js:59–61

(regex)

        // XRegExp follows the native RegExp. Chrome 20 follows the spec and converts empty
        // patterns to (?:), but Firefox 14.0.1, Safari 5.1.2, Opera 12, and IE 9 do not
        function isEmpty(regex) {
            return regex.source === '(?:)' || regex.source === '';
        }

        emptyTypes.forEach(function(item) {
            expect(isEmpty(XRegExp(item))).toBe(true);