code: function detectWebEnvironment(environments) {
      // If the given environment is just a Closure, we will defer the environment check
      // to the Closure the developer has provided, which allows them to totally swap
      // the webs environment detection logic with their own custom Closure's code.
      if (typeof environments === 'function') {
          return environments()
      }
  
      var hosts;
      for (var environment in environments) {
          hosts = environments[environment];
  
          // To determine the current environment, we'll simply iterate through the possible
          // environments and look for the host that matches the host for this request we
          // are currently processing here, then return back these environment's names.
          hosts = helper.parseObject(hosts);
          var k, host;
          for (k in hosts) {
              host = hosts[k];
              if (isMachine(host)) return environment;
          }
      }
  
      return 'production';
  }
docs: Set the application environment for a web request.
  
  @param {Object|function} environments
  @return string