var UNICODE = '\\\\[0-9a-f]{1,6}(\\r\\n|[ \\n\\r\\t\\f])?'; var ESCAPE = '(' + UNICODE + '|\\\\[^\\n\\r\\f0-9a-fA-F])'; var NONPRINTABLE = '\u0000\u0008\u000b\u000e-\u001f\u007f'; var SAFE_URL = new RegExp('^(' + ESCAPE + '|[^\"\'\\(\\)\\\\\\s' + NONPRINTABLE + '])*$', 'i'); module.exports = function(node) { var value = node.value; if (value.type !== 'String') { return; } var quote = value.value[0]; var url = value.value.substr(1, value.value.length - 2); // convert `\\` to `/` url = url.replace(/\\\\/g, '/'); // remove quotes when safe // https://www.w3.org/TR/css-syntax-3/#url-unquoted-diagram if (SAFE_URL.test(url)) { node.value = { type: 'Raw', info: node.value.info, value: url }; } else { // use double quotes if string has no double quotes // otherwise use original quotes // TODO: make better quote type selection node.value.value = url.indexOf('"') === -1 ? '"' + url + '"' : quote + url + quote; } };