code: function assignIfFunction(name, toObj, fromObj, where) {
      if ('undefined' !== typeof fromObj[name]) {
          if ('function' !== typeof fromObj[name]) {
              new TypeError((where || 'WaitingRoom.parseSettings: ') + name +
                            'must be function or undefined. Found: ' +
                            fromObj[name]);
          }
          toObj[name] = fromObj[name];
      }
  }
docs: ## assignIfFunction
  
  Assigns a property to an object from another one if it is a function
  
  The property in the object must be undefined or function, otherwise
  an error will be raised.
  
  @param {string} name The name of the property to verify and assign
  @param {object} toObj The object to which the property will be assigned
  @param {object} fromObj The object from which the property will be copied
  @param {string} where A prefix for the error message. Default:
  'WaitingRoom.parseSettings: '.