Function parseHeaders

src/document-fetcher.js:114–128

* Parses XHR's response headers into JSONObject. * @param {string} rawHeaders * @return {!JsonObject}

(rawHeaders)

 * @return {!JsonObject}
 */
function parseHeaders(rawHeaders) {
  const headers = {};
  // Replace instances of \r\n and \n followed by at least one space or
  // horizontal tab with a space.
  const preProcessedHeaders = rawHeaders.replace(/\r?\n[\t ]+/g, ' ');
  preProcessedHeaders.split(/\r?\n/).forEach(function (line) {
    const parts = line.split(':');
    const key = parts.shift().trim();
    if (key) {
      const value = parts.join(':').trim();
      headers[key] = value;
    }
  });
  return headers;
}