hed.content);
      map.xScopes = parsedJSON["x-scopes"];
    }
  }

  // Extend the default map object with sourceMapBaseURL, used to check further
  // network requests made for this sourcemap.
  map.sourceMapBaseURL = generatedSource.sourceMapBaseURL;

  if (map && map.sources) {
    map.sources.forEach(url => originalURLs.add(url));
  }

  return map;
}

function fetchSourceMap(generatedSource, resolvedSourceMapURL, baseURL) {
  const existingRequest = getSourceMap(generatedSource.id);

  // If it has already been requested, return the request. Make sure
  // to do this even if sourcemapping is turned off, because
  // pretty-printing uses sourcemaps.
  //
  // An important behavior here is that if it's in the middle of
  // requesting it, all subsequent calls will block on the initial
  // request.
  if (existingRequest) {
    return existingRequest;
  }

  if (!generatedSource.sourceMapURL) {
    return null;
  }

  // Fire off the request, set it in the cache, and return it.
  const req = _fetch(generatedSource, resolvedSourceMapURL, baseURL);
  // Make sure the cached promise does not reject, because we only
  // want to report the error once.
  setSourceMap(
    generatedSource.id,
    req.catch(() => null)
  );
  return req;
}

module.exports = {
  fetchSourceMap,
  hasOriginalURL,
  clearOriginalURLs,
  resolveSourceMapURL,
};
PK