code: function createPathRewriter(rewriteConfig) {
      let rulesCache;
      if (!isValidRewriteConfig(rewriteConfig)) {
          return;
      }
      if (_.isFunction(rewriteConfig)) {
          const customRewriteFn = rewriteConfig;
          return customRewriteFn;
      }
      else {
          rulesCache = parsePathRewriteRules(rewriteConfig);
          return rewritePath;
      }
      function rewritePath(path) {
          let result = path;
          _.forEach(rulesCache, rule => {
              if (rule.regex.test(path)) {
                  result = result.replace(rule.regex, rule.value);
                  logger.debug('[HPM] Rewriting path from "%s" to "%s"', path, result);
                  return false;
              }
          });
          return result;
      }
  }
docs: Create rewrite function, to cache parsed rewrite rules.
  
  @param {Object} rewriteConfig
  @return {Function} Function to rewrite paths; This function should accept `path` (request.url) as parameter